Adeno-associated virus with engineered capsid

ABSTRACT

The present disclosure provides recombinant adeno-associated virus (rAAV) virions with an engineered capsid protein identified using a high-throughput sequencing screen or rational design. In particular, the disclosure provides AAV5 virions and capsid proteins with increased transduction efficiency in cardiac cells, increased cell-type selectivity, and/or other desirable properties.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. Provisional Application No. 62/984,197, filed Mar. 2, 2020, and U.S. Provisional Application No. 62/827,576, filed Apr. 1, 2019, the disclosures of which are incorporated by reference in their entireties for all purposes.

FIELD OF THE INVENTION

The present disclosure relates generally to gene therapy with adeno-associated virus vectors. In particular, the disclosure relates to recombinant adeno-associated virus virions having an engineered capsid protein.

REFERENCE TO SEQUENCE LISTING

This application is being filed electronically via EFS-Web and includes an electronically submitted sequence listing in .txt format. The .txt file contains a sequence listing entitled “TENA_012_02WO_SeqList_ST25.txt” created on Mar. 31, 2020 and having a size of ˜2,590 kilobytes. The sequence listing contained in this .txt file is part of the specification and is incorporated herein by reference in its entirety.

BACKGROUND

Adeno-associated virus (AAV) holds promise for gene therapy and other biomedical applications. In particular, AAV can be used to deliver gene products to various tissues and cells, both in vitro and in vivo. The capid proteins of AAV largely determine the immunogenicity and tropism of AAV vectors.

For some tissues, AAV subtype 5 (AAV5) is a preferred AAV vector due to the low prevalence of neutralizing antibodies against AAV5 in human populations. AAV5 transduces cardiac tissues less effectively, however, than other AAV subtypes. In addition, selective transduction of different cell types is desirable but difficult to achieve. For example, in some applications, transduction of cardiac fibroblasts rather than cardiac myocytes, or vice-versa, may be desirable. The present disclosure provides variants of the AAV5 capsid that form rAAV virions capable of transducing cardiac tissues and/or cell types for more efficiently and/or with more selectivity than rAAV virions comprising wild-type AAV5 capsid proteins.

SUMMARY OF THE DISCLOSURE

In one aspect, the disclosure provides a recombinant adeno-associated virus (rAAV) virion, comprising an AAV5 capsid protein, wherein the capsid protein comprises one or more substitutions selected from S651A, S651G, S651V, S651L, S651I, T578A, T578G, T578V, T578L, T578I, T582A, T582G, T582V, T582L, or T582I compared to a parental AAV5 capsid; and a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product.

In another aspect, the disclosure provides an AAV5 capsid protein comprising one or more substitutions selected from S651A or S651V; T578A or T578V; or T582A or T582V compared to a parental AAV5 capsid.

In another aspect, the disclosure provides recombinant adeno-associated virus (rAAV) virion, comprising an AAV5 capsid protein, wherein the capsid protein comprises an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence; and a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product.

In another aspect, the disclosure provides an AAV5 capsid protein, wherein the capsid protein comprises an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence.

In a further aspect, the disclosure provides a polynucleotide encoding the AAV5 capsid protein, wherein the capsid protein comprises an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence.

In a further aspect, the disclosure provides a pharmaceutical composition comprising an rAAV virion comprising an AAV5 capsid protein, wherein the capsid protein comprises an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence; and a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product.

In a further aspect, the disclosure provides method of transducing a cardiac cell, comprising contacting the cardiac cell with an rAAV virion of the disclosure, wherein the rAAV virion transduces the cardiac cell.

In a further aspect, the disclosure provides a method of delivering one or more gene products to a cardiac cell, comprising contacting the cardiac cell with an rAAV virion of the disclosure, wherein the cardiac cell expresses the gene product.

In a further aspect, the disclosure provides a method of treating a cardiac pathology in a subject in need thereof, comprising administering a therapeutically effective amount of a pharmaceutical composition comprising an rAAV virion of the disclosure, wherein the rAAV virion transduces cardiac tissue.

In a further aspect, the disclosure provides a method of identifying AAV capsid proteins that confer on rAAV virions increased transduction efficiency in target cells, comprising providing a population of rAAV virions whose rAAV genomes comprise a library of cap polynucleotides encoding variant AAV capsid proteins; contacting the population with target cells for a time sufficient to permit transduction of the cap polynucleotide into the target cells by the rAAV virions; and sequencing the cap polynucleotides from the target cells, thereby identifying AAV capsid proteins that confer increased transduction efficiency in the target cells.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of a library screening strategy incorporating an initial negative selection step on induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) followed by a positive selection step on human cardiac fibroblasts (hCFs).

FIGS. 2A-2B depict generation of an AAV5 random peptide display library and mapping onto the crystal structure of AAV5. FIG. 2A shows a schematic of an AAV genome comprising the rep gene of AAV2 (“Rep2”) and the cap gene of AAV (“Cap5”) flanked by 3′ and 5′ inverted terminal repeats (ITRs). In this embodiment, a random 7-mer polypeptide library flanked by alanine residues (AXXXXXXXA; SEQ ID NO: 100) is inserted at position 575 as indicated. FIG. 2B shows the structure of the AAV5 capsid. The approximate insertion site for polypeptide library (in one of the 60 copies of the capsid protein shown) is indicated by a black arrow.

FIGS. 3A-3D visualize library complexity following each round of screening and report total number of reads and percentage of reads that are unique peptides. Each variant is represented by a different shade of gray based on the hydrophobicity of the peptide sequence, and each pixel in the image represents a single read in the library and is clustered with other reads of the same sequence. Increasing enrichment is evident based on over-abundance of reads (i.e. decrease in the percentage of reads that are unique peptides) compared to the parental library (FIG. 3A) after round 1 (FIG. 3B), after round 2(FIG. 3C), or after round 3 (FIG. 3D).

FIGS. 4A-4D shows transduction efficiency for hCF cells of various rAAV virions identified using the library screening strategy. FIG. 4A shows transduction efficiency of fifteen AAV5 variants benchmarked against unmodified AAV5 (right most bar) packaging a green fluorescent protein (GFP) reporter transgene. hCFs were infected at a genomic multiplicity of infection (MOI) of 100,000 and the percentage of GFP positive cells were quantified using the Cytation 5™ cell imaging multi-mode reader. Representative fluorescent images are shown for hCFs transduced by either unmodified AAV5 (FIG. 4B) or AAV5.CR17 (FIG. 4C). FIG. 4D shows transduction efficiency of unmodified AAV5 versus AAV.CR17 at MOI of 1,000.

FIGS. 5A-5D shows transduction efficiency for iPS-CM cells of various rAAV virions identified using the library screening strategy. FIG. 5A shows transduction efficiency of fifteen AAV5 variants benchmarked against unmodified AAV5 (right most bar) packaging a GFP reporter transgene. hCFs were infected at a genomic multiplicity of infection (MOI) of 100,000 and the percentage of GFP positive cells were quantified using the Cytation 5™ cell imaging multi-mode reader. Representative fluorescent images are shown for hCFs transduced by either unmodified AAV5 (FIG. 5B) or AAV5.CR23 (FIG. 5C). FIG. 5D shows transduction efficiency of unmodified AAV5 versus AAV.CR23 at MOI of 100,000.

FIGS. 6A-6E demonstrate that AAV5.CR17 has improved transduction efficiency in primary mouse cardiac fibroblasts (mCFs). mCFs were infected at a high (100,000) medium (10,000) or low (1,000) MOI with either AAV5.CAG-GFP or AAV5.CR17.CAG-GFP. 72 hours following infection, transduction was assessed using flow cytometry. FIG. 6A shows a histogram and gating of “total GFP” and “high GFP” populations. Increased percent GFP+(FIG. 6B) and GFP intensity (FIG. 6C) were observed in the “total GFP” population when cells were transduced with AAV5.CR17 compared to unmodified AAV5 at MOI of 103, 104, or 105.

Increased percent GFP+(FIG. 6D) and GFP intensity (FIG. 6E) were observed in the “high GFP” population when cells were transduced with AAV5.CF17 compared to unmodified AAV5 at MOI of 103, 104, or 105.

FIGS. 7A-7H show the transduction profile of AAV5 and AAV5.CR17 in CD1 mice with and without myocardial infarction (MI). Unmodified AAV5 exhibited limited transduction of cardiac tissue in control mice (GFP—FIG. 7A; DAPI—FIG. 7B) or induced MI mice (GFP—FIG. 7C; DAPI—FIG. 7D). AAV5.CR17 more effectively transduced cardiac tissue in both control mice (GFP—FIG. 7E; DAPI—FIG. 7F) and induced MI mice (GFP—FIG. 7G; DAPI—FIG. 7H). 1.2×10¹¹ vg of either AAV5.CAG-GFP or AAV5.CR17.CAG-GFP was injected into 6-week old CD1 mice via an intramyocardial injection. GFP intensity and distribution was assessed 7 days following an injection. Increased cardiomyocyte and fibroblast transduction is observed with AAV5.CR17 in both non-MI and MI animals. All heart tissue sections were imaged using a 20× objective with equal gain and exposure. Anti-GFP immunostaining is shown in green and nuclei counterstaining with DAPI blue is shown in blue.

FIGS. 8A-8E show sequence motifs based on the sequence of the top 100 (FIG. 8A), top 50 (FIG. 8B), top 20 (FIG. 8C) sequences in Table 2 (SEQ ID NOs. 101-600), or the sequences with data reported in Table 1 (FIG. 8D) (SEQ ID NOs. 101-115). FIG. 8E shows a sequence motif for all sequence reads in the library weighted by the number of sequence reads in the library after round 3 (SEQ ID NOs. 101-600).

FIG. 9 show AAV5 surface-exposed serine/threonine/lysine/tyrosine mutant vectors demonstrate increased transduction efficiency of hCFs in vitro. hCF cells were infected with either AAV5-wt or AAV5-mutant vectors packaging a ubiquitously expressing GFP reporter. Substitutions S651A, T578A, or T582A in the AAV5 capsid resulted in improved human cardiac fibroblast transduction at an multiplicity of infection of 100,000 vg/cell 72 hours following infection.

FIGS. 10A-10C show transduction of human cardiac fibroblasts (hCFs) with either AAV×1 vector (top lines) or AAV5 vector (bottom lines). FIG. 10A shows percentage of transduced cells. FIG. 10B shows GFP transgene expression. FIG. 10C shows relative transduction (Relative Transduction=Transduced Cells (%)×Cell Intensity).

FIG. 11 shows relative transduction of cardiac fibroblast (CF) cell in vivo.

FIG. 12 shows AAV×1 vector with MyA expression cassette is efficacious against myocardial infarction by kinetic echocardiography data of % ejection fraction.

FIG. 13 shows a graph of the change in percent ejection fraction of treated and untreated pigs with ischemic injury, up to nine weeks post-injection.

DETAILED DESCRIPTION

The present disclosure relates generally to recombinant adeno-associated virus (rAAV) virions for use as viral vectors having capsid proteins with (1) substitutions at selected surface-exposed amino acid residues; (2) insertions in the GH loop; or (3) both. The rAAV virions may transduce cardiac tissues, e.g. cardiac fibroblasts, at least as well or better than rAAV virions having parental capsid proteins without these substitutions and/or insertions.

The disclosure provides recombinant adeno-associated virus (rAAV) virions. In particular, the disclosure provides new capsid proteins, methods of identifying them, and methods of using them. The methods of identifying new capsid proteins disclosed herein have wide applicability for any serotype of AAV, including hybrid capsid proteins. In addition, they can be applied to iteratively improve capsid proteins that have mutations from this or other methods. In general, the methods of the disclosure relate to preparation of randomized or semi-randomized libraries of AAV capsids in the form of cap gene polynucleotides, preparation of AAV virions comprising such capsids (either by incorporating the cap gene library into an AAV genome or providing it in trans such as on a plasmid transfected into the packaging line), positively or negatively selecting the AAV virions, and recovering the cap gene for sequencing. In some embodiments, the recovery and sequencing include nanopore sequencing. Other high-throughput or next-generation-sequencing (NGS) methods can be used.

In some embodiments, the rAAV virions disclosed herein comprise an AAV5 capsid protein, wherein the capsid protein comprises an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence. The rAAV virions generally comprise a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product. Suitable insertion sites for the insertion can be determined by various methods, including but not limited to modeling the GH loop based on the crystal structure of the AAV5 capsid; by selecting flexible residues; or by screening various insertion sites. The insertion may be between two adjacent amino acids residues, or non-adjacent residues may be selected, in which case the insertion causes a deletion of one or more intervening residues.

In some embodiments, the AAV5 capsid protein comprises substitutions of residues that are either rationally designed; introduced by mutagenesis; or randomized through generating a library of sequences with random codon usage at one or more sites. Exemplary non-limiting substitutions that inflect transfection efficiency include, but are not limited to S651A, T578A or T582A. The substituted residues may be incorporated into AAV5 capsid proteins that further comprise insertions at one or more insertion sites, e.g. the GH loop or other loops.

The capsid proteins of the disclosure include any insertion identified as enriched by directed evolution followed by sequence, as shown in, but not limited to, the Examples. Without being limited to any particular insertion site, in some embodiments, the insertion is between about residues 574 and 575 in the AAV5 capsid protein (SEQ ID NO: 1). In some embodiments, the insertion site is between any two, optionally adjacent, amino acids at positions in the parental sequence corresponding to 560 to 594 of SEQ ID NO: 1. In some embodiments, the insertion site is between adjacent amino acids in the parental sequence corresponding to 574 and 575 of SEQ ID NO: 1. The N-terminal residue of VP1, VP2, and VP3 are indicated above the sequence of full-length VP1.

(SEQ ID NO: 1) VP1--> M SFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK                                   VP2--> LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAK T APTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN                     VP3--> NQGADGVGNASGDWHCDSTW M GDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV              ↓ Insertion site 575 AYNVGGQMATNNQ_SSTTAPATGTYNLQEIVPGSVWMERDVYLQGPIWAKI PETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSFSDVPVSSFITQY STGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTR PIGTRYLTRPL

An insertion at this insertion site divides the VP3 capsid protein into an N-terminal segment (SEQ ID NO: 2) and a C-terminal segment (SEQ ID NO: 3), disclosed as distinct sequences herein for clarity, which may joined by any of the insertions of the disclosure. In some embodiments, the capsid protein comprises a sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 1 (for clarity, with a gap in the alignment at the insertion site). In some embodiments, the capsid protein comprises a sequence that shares at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identity to SEQ ID NO: 2 and that shares at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identity to SEQ ID NO: 3, where SEQ ID NO: 2 and SEQ ID NO: 3 are linked by an insertion of 5 to 11 amino acids. In some embodiments, the insertion is selected from SEQ ID NOs: 101-600. In some embodiments, the flanking alanine (A) residues of SEQ ID NOs: 101-600 are substituted with other residues, such as flexible residues serine (S) or glycine (G), the flanking A residues are absent.

(SEQ ID NO: 2) MGDRVVTKSTRTWVLPSYNNHQYREIKSGSVDGSNANAYFGYSTPWGYFDF NRFHSHWSPRDWQRLINNYWGFRPRSLRVKIFNIQVKEVTVQDSTTTIANN LTSTVQVFTDDDYQLPYVVGNGTEGCLPAFPPQVFTLPQYGYATLNRDNTE NPTERSSFFCLEYFPSKMLRTGNNFEFTYNFEEVPFHSSFAPSQNLFKLAN PLVDQYLYRFVSTNNTGGVQFNKNLAGRYANTYKNWFPGPMGRTQGWNLGS GVNRASVSAFATTNRMELEGASYQVPPQPNGMTNNLQGSNTYALENTMIFN SQPANPGTTATYLEGNMLITSESETQPVNRVAYNVGGQMATNNQ (SEQ ID NO: 3) SSTTAPATGTYNLQEIVPGSVWMERDVYLQGPIWAKIPETGAHFHPSPAMG GFGLKHPPPMMLIKNTPVPGNITSFSDVPVSSFITQYSTGQVTVEMEWELK KENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRPIGTRYLTRPL

In some embodiments, the capsid protein comprising a sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 4, where X represents any amino acid. In some embodiments, the capsid protein comprising a sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 5, where X represents any amino acid.

(SEQ ID NO: 4) MGDRVVTKSTRTWVLPSYNNHQYREIKSGSVDGSNANAYFGYSTPWGYFDF NRFHSHWSPRDWQRLINNYWGFRPRSLRVKIFNIQVKEVTVQDSTTTIANN LTSTVQVFTDDDYQLPYVVGNGTEGCLPAFPPQVFTLPQYGYATLNRDNTE NPTERSSFFCLEYFPSKMLRTGNNFEFTYNFEEVPFHSSFAPSQNLFKLAN PLVDQYLYRFVSTNNTGGVQFNKNLAGRYANTYKNWFPGPMGRTQGWNLGS GVNRASVSAFATTNRMELEGASYQVPPQPNGMTNNLQGSNTYALENTMIFN SQPANPGTTATYLEGNMLITSESETQPVNRVAYNVGGQMATNNQ XXXXXXX XX SSTTAPATGTYNLQEIVPGSVWMERDVYLQGPIWAKIPETGAHFHPSPA MGGFGLKHPPPMMLIKNTPVPGNITSFSDVPVSSFITQYSTGQVTVEMEWE LKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRPIGTRYLTRPL (SEQ ID NO: 5) MGDRVVTKSTRTWVLPSYNNHQYREIKSGSVDGSNANAYFGYSTPWGYFDF NRFHSHWSPRDWQRLINNYWGFRPRSLRVKIFNIQVKEVTVQDSTTTIANN LTSTVQVFTDDDYQLPYVVGNGTEGCLPAFPPQVFTLPQYGYATLNRDNTE NPTERSSFFCLEYFPSKMLRTGNNFEFTYNFEEVPFHSSFAPSQNLFKLAN PLVDQYLYRFVSTNNTGGVQFNKNLAGRYANTYKNWFPGPMGRTQGWNLGS GVNRASVSAFATTNRMELEGASYQVPPQPNGMTNNLQGSNTYALENTMIFN SQPANPGTTATYLEGNMLITSESETQPVNRVAYNVGGQMATNNQ AXXXXXX XA SSTTAPATGTYNLQEIVPGSVWMERDVYLQGPIWAKIPETGAHFHPSPA MGGFGLKHPPPMMLIKNTPVPGNITSFSDVPVSSFITQYSTGQVTVEMEWE LKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRPIGTRYLTRPL

In some embodiments, the insertion is a peptide of formula

-X₀-(X)_(n)-X₁₀-

wherein n is 5-9, and wherein X₀ and X₁₀ are each independently A, S, G, or absent (SEQ ID NO: 1101).

In some embodiments, the insertion is a peptide of formula:

-X₀-X₁-X₂-X₃-X₄-X₅-X₆-X₇-X₈-

wherein X₀ and X₈ are each independently A, S, G, or absent (SEQ ID NO: 1102).

In some embodiments, the insertion is a peptide of formula:

-A-X₁-X₂-X₃-X₄-X₅-X₆-X₇-A-

wherein X₁ is P, R, or G; X₂ is K, L, or R; X₃ is any amino acid; X₄ is N, H, K, or Q; X₅ is any amino acid, or optionally X₅ is G, K, or S; X₆ is any amino acid, or optionally X₆ is T or V; and X₇ is any amino acid, or optionally X₇ is K or V (SEQ ID NO: 1103).

In some embodiments, the insertion is a peptide of formula:

-A-X₁-X₂-X₃-X₄-X₅-X₆-X₇-A-

wherein X₁ is P, R, or G; X₂ is K, L, or R; X₃ is any amino acid; X₄ is N, H, K, or Q; X₅ is any amino acid, or optionally X₅ is G, K, or S; X₆ is any amino acid; and X₇ is any amino acid (SEQ ID NO: 1104).

In some embodiments, the insertion is a peptide of formula:

-A-X₁-X₂-X₃-X₄-X₅-X₆-X₇-A-

wherein X₁ is P, R, or G; X₂ is K, L, or R; X₃ is any amino acid; X₄ is N, H, K, or Q; X₅ is any amino acid, or optionally X₅ is G, K, or S; X₆ is T or V; and X₇ is any amino acid (SEQ ID NO: 1105).

In some embodiments, the insertion is a peptide of formula:

-A-X₁-X₂-X₃-X₄-X₅-X₆-X₇-A-

wherein X₁ is P, R, or G; X₂ is K, L, or R; X₃ is any amino acid; X₄ is N, H, K, or Q; X₅ is any amino acid, or optionally X₅ is G, K, or S; X₆ is T or V; and X₇ is K or V (SEQ ID NO: 1106).

In some embodiments, X₁ through X₇ are any amino acid, wherein the insertion is defined by one or more of the following criteria: X₁ is P, R, or G; X₂ is K, L, or R; X₃ is any amino acid; X₄ is N, H, K, or Q; X₅ is X₅ is G, K, or S; X₆ is T or V; and/or X₇ is X₇ is K or V (SEQ ID NO: 1107).

In some embodiments, the insertion is selected from SEQ ID NOs: 101-600.

In some embodiments, the capsid protein comprises, in N-terminal to C-terminal order, one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 3; one polypeptide selected from SEQ ID NOs 101-600; and one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2.

In some embodiments, the capsid protein comprises, in N-terminal to C-terminal order, one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 3; one polypeptide selected from SEQ ID NOs: 101-200; and one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2.

In some embodiments, the capsid protein comprises, in N-terminal to C-terminal order, one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 3; one polypeptide selected from SEQ ID NOs: 101-150; and one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2.

In some embodiments, the capsid protein comprises, in N-terminal to C-terminal order, one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 3; one polypeptide selected from SEQ ID NOs: 101-120; and one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2.

In some embodiments, the capsid protein comprises, in N-terminal to C-terminal order, one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 3; one polypeptide selected from SEQ ID NOs: 101-115; and one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2.

In some embodiments, the capsid protein comprises, in N-terminal to C-terminal order, one polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 3; one polypeptide selected from SEQ ID NOs: 103 or 110; and one polypeptide having sequence at least about 80%, 85%, 90°/, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2 and at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to SEQ ID NO: 2.

In some embodiments, the capsid protein comprises, consists essentially of, or consists of a polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to one of SEQ ID NOs 601-1100, or a functional fragment thereof.

In some embodiments, the capsid protein comprises, consists essentially of, or consists of a polypeptide having sequence at least about 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, or 100% identical to one of SEQ ID NOs 601-615, or a functional fragment thereof.

In some embodiments, the insertion comprises an amino acid sequence selected from RKVHIEV (SEQ ID NO: 81), RKYQSDL (SEQ ID NO: 82), PLTNTVK (SEQ ID NO: 83), LKYHGPP (SEQ ID NO: 84), RKYQGDM (SEQ ID NO: 85), RKFHSTD (SEQ ID NO: 86), RKHHGLE (SEQ ID NO: 87), PGTNVTK (SEQ ID NO: 88), RKMHMPD (SEQ ID NO: 89), PLKKIVQ (SEQ ID NO: 90), PLGKKTS (SEQ ID NO: 91), PRGVKVT (SEQ ID NO: 92), PLAKSKS (SEQ ID NO: 93), PRTKGAV (SEQ ID NO: 94), and PSGRKAT (SEQ ID NO: 95).

In some embodiments, the insertion comprises an amino acid sequence selected from ARKVHIEVA (SEQ ID NO: 101), ARKYQSDLA (SEQ ID NO: 102), APLTNTVKA (SEQ ID NO: 103), ALKYHGPPA (SEQ ID NO: 104), ARKYQGDMA (SEQ ID NO: 105), ARKFHSTDA (SEQ ID NO: 106), ARKHHGLEA (SEQ ID NO: 107), APGTNVTKA (SEQ ID NO: 108), ARKMHMPDA (SEQ ID NO: 109), APLKKIVQA (SEQ ID NO: 110), APLGKKTSA (SEQ ID NO: 111), APRGVKVTA (SEQ ID NO: 112), APLAKSKSA (SEQ ID NO: 113), APRTKGAVA (SEQ ID NO: 114), APSGRKATA (SEQ ID NO: 115).

In some embodiments, the insertion comprises any one of SEQ ID NOs: 101-600. In some embodiments, a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to any one of SEQ ID NOs: 101-600.

In some embodiments, the insertion comprises the amino acid sequence PLTNTVK (SEQ ID NO: 83) (clone CR17) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLTNTVK (SEQ ID NO: 83).

In some embodiments, the insertion comprises the amino acid sequence PLKKIVQ (SEQ ID NO: 90) (clone CR23) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLKKIVQ (SEQ ID NO: 90).

In some embodiments, the the insertion comprises the amino acid sequence APLTNTVKA (SEQ ID NO: 103) (clone CR17) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to APLTNTVKA (SEQ ID NO: 103).

In some embodiments, the the insertion comprises the amino acid sequence APLKKIVQA (SEQ ID NO: 110) (clone CR23), wherein the insertion further comprises 1, 2, 3, or 4 conservative amino-acid substitutions.

In some embodiments, the insertion comprises the amino acid sequence PLTNTVK (SEQ ID NO: 83) (clone CR17), wherein the insertion further comprises 1, 2, 3, or 4 conservative amino-acid substitutions.

In some embodiments, the insertion comprises the amino acid sequence PLKKIVQ (SEQ ID NO: 90) (clone CR23), wherein the insertion further comprises 1, 2, 3, or 4 conservative amino-acid substitutions.

In some embodiments, the the insertion comprises the amino acid sequence APLTNTVKA (SEQ ID NO: 103) (clone CR17), wherein the insertion further comprises 1, 2, 3, or 4 conservative amino-acid substitutions.

In some embodiments, the the insertion comprises the amino acid sequence at least APLKKIVQA (SEQ ID NO: 110) (clone CR23), wherein the insertion further comprises 1, 2, 3, or 4 conservative amino-acid substitutions.

Conservative substitutions include polar for polar residues, non-polar for non-polar residues, hydrophobic for hydrophobic resides, small for small residues, and large for large residues. Conservative substitutions further comprise substitutions within the following groups: {S, T}, {A, G}, {F, Y}, {R, H, K, N, E}, {S, T, N, Q}, {C, U, G, P; A}, and {A, V, I, L, M, F, Y, W}.

Transduction efficiently can be determined using methods known in the art or those described in the Examples. In some embodiments, the rAAV virion exhibits increased transduction efficiency in cardiac cells compared to an AAV virion comprising the parental sequence.

In some embodiments, the rAAV virion exhibits increased transduction efficiency in human cardiac fibroblast (hCF) cells compared to an AAV virion comprising the parental sequence.

In some embodiments, the rAAV virion exhibits at least 2-, 3-, 4-, 5-, 6, 7-, 8-, 9-, 10, 11-, 12-, 13-, 14, or 15-fold increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 100,000. In some embodiments, the rAAV virion exhibits about 2- to about 16-fold, about 2- to about 14-fold, about 2- to about 12-fold, about 2- to about 10-fold, about 2- to about 8-fold, about 2- to about 6-fold, about 2- to about 4-fold, or about 2- to about 3-fold increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 100,000. In some embodiments, the rAAV virion exhibits at least 2-, 3-, 4-, 5-, 6, 7-, 8-, 9-, 10, 11-, 12-, 13-, 14, or 15-fold increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 100,000. In some embodiments, the rAAV virion exhibits about 20% to 30%, about 30% to 40%, about 40% to 50%, about 50% to 80%, about 80% to 100%, about 100% to 125%, about 125% to 150%, about 150% to 175%, or about 175% to 200% increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 100,000.

In some embodiments, the rAAV virion exhibits at least 2-, 3-, 4-, 5-, 6, 7-, 8-, 9-, 10, 11-, 12-, 13-, 14, or 15-fold increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 1,000. In some embodiments, the rAAV virion exhibits about 2- to about 16-fold, about 2- to about 14-fold, about 2- to about 12-fold, about 2- to about 10-fold, about 2- to about 8-fold, about 2- to about 6-fold, about 2- to about 4-fold, or about 2- to about 3-fold increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 1,000. In some embodiments, the rAAV virion exhibits about 20% to 30%, about 30% to 40%, about 40% to 50%, about 50% to 80%, about 80% to 100%, about 100% to 125%, about 125% to 150%, about 150% to 175%, or about 175% to 200% increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 1,000.

In some embodiments, the rAAV virion exhibits increased transduction efficiency in induced pluripotent stem cell-derived cardiomyocyte (iPS-CM) cells compared to an AAV virion comprising the parental sequence.

In some embodiments, the rAAV virion exhibits at least 2-, 3-, 4-, 5-, 6, 7-, 8-, 9-, 10, 11-, 12-, 13-, 14, or 15-fold increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 100,000. In some embodiments, the rAAV virion exhibits about 2- to about 16-fold, about 2- to about 14-fold, about 2- to about 12-fold, about 2- to about 10-fold, about 2- to about 8-fold, about 2- to about 6-fold, about 2- to about 4-fold, or about 2- to about 3-fold increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 100,000. In some embodiments, the rAAV virion exhibits about 20% to 30%, about 30% to 40%, about 40% to 50%, about 50% to 80%, about 80% to 100%, about 100% to 125%, about 125% to 150%, about 150% to 175%, or about 175% to 200% increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 100,000.

In some embodiments, the rAAV virion exhibits at least 2-, 3-, 4-, 5-, 6, 7-, 8-, 9-, 10, 11-, 12-, 13-, 14, or 15-fold increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 1,000. In some embodiments, the rAAV virion exhibits about 2- to about 16-fold, about 2- to about 14-fold, about 2- to about 12-fold, about 2- to about 10-fold, about 2- to about 8-fold, about 2- to about 6-fold, about 2- to about 4-fold, or about 2- to about 3-fold increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 1,000. In some embodiments, the rAAV virion exhibits about 20% to 30%, about 30% to 40%, about 40% to 50%, about 50% to 80%, about 80% to 100%, about 100% to 125%, about 125% to 150%, about 150% to 175%, or about 175% to 200% increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 1,000.

Selectivity for a cell type is increased when the ratio of the transduction efficiencies for one cell type over another is increased by the capsid protein compared to a parental sequence. In some embodiments, the rAAV virion exhibits increased selectivity of the rAAV virion for hCF cells over iPS-CM cells.

In some embodiments, the rAAV virion exhibits increased selectivity of the rAAV virion for iPS-CM cells over hCF cells.

In some embodiments, the capsid protein comprises a mutation selected from S651A, T578A, T582A, K251R, Y709F, Y693F, or S485A. In some embodiments, the capsid protein comprises a mutation selected from K251R, Y709F, Y693F, or S485A.

The polynucleotide encoding the capsid protein can comprise a sequence comprising either the native codons of the wild-type cap gene, or alternative codons selected to encode the same protein. The codon usage of the insertion can be varied. Representative nucleotide sequences for cap genes encoding capsid proteins of the disclosure are provided as SEQ ID NOs 51-72. In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to one of SEQ ID NOs 51-72. It is within the skill of those in the art to select appropriate nucleotide sequences and to derive alternative nucleotide sequences to encode any capsid protein of the disclosure. Reverse translation of the protein sequence can be performed using the codon usage table of the host organism, i.e. Eukaryotic codon usage for humans.

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 51 {CR2 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 101 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to ARKVHIEVA (SEQ ID NO: 101).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 52 {CR5 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 102 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to ARKYQSDLA (SEQ ID NO: 102).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 53 {CR8 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 107 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to ARKHHGLEA (SEQ ID NO: 107).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 54 {CR17 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 103 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to APLTNTVKA (SEQ ID NO: 103).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 55 {CR18 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 104 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to ALKYHGPPA (SEQ ID NO: 104).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 56 {CR19 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 105 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to ARKYQGDMA (SEQ ID NO: 105).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 57 {CR20 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 106 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to ARKFHSTDA (SEQ ID NO: 106).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 58 {CR21 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 108 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to APGTNVTKA (SEQ ID NO: 108).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 59 {CR22 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 109 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to ARKMHMPDA (SEQ ID NO: 109).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 60 {CR23 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 110 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to APLKKIVQA (SEQ ID NO: 110).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 61 {CR24 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 111 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to APLGKKTSA (SEQ ID NO: 111).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 62 {CR25 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 112 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to APRGVKVTA (SEQ ID NO: 112).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 63 {CR26 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 113 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to APLAKSKSA (SEQ ID NO: 113).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 64 {CR27 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 114 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to APRTKGAVA (SEQ ID NO: 114).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 65 {CR28 polynucleotide sequence}, wherein the AAV5 capsid protein comprises SEQ ID NO: 115 or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to APSGRKATA (SEQ ID NO: 115).

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 66, wherein the AAV5 capsid protein comprises the substitution K251R with respect to SEQ ID NO: 1.

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 67, wherein the AAV5 capsid protein comprises the substitution S485A with respect to SEQ ID NO: 1.

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 68, wherein the AAV5 capsid protein comprises the substitution S651A with respect to SEQ ID NO: 1.

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 69, wherein the AAV5 capsid protein comprises the substitution T578A with respect to SEQ ID NO: 1.

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 70, wherein the AAV5 capsid protein comprises the substitution T582A with respect to SEQ ID NO: 1.

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 71, wherein the AAV5 capsid protein comprises the substitution Y709F with respect to SEQ ID NO: 1.

In some embodiments, the disclosure provides a polynucleotide encoding an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to SEQ ID NO: 72, wherein the AAV5 capsid protein comprises the substitution Y693F with respect to SEQ ID NO: 1.

In some embodiments, the disclosure provides an AAV5 capsid protein comprising a sequence at least 95%, 99%, or 100% identical to a modified capsid selected from SEQ ID NOs: 9-34, wherein the substitutions in the modified capsid from the reference capsid SEQ ID NO: 1 are present, and wherein other substitutions, optionally conservative substitutions, with the specified percent identity level are tolerated.

In some embodiment, the insertion site is between any two, optionally adjacent, amino acids at positions in the parental sequence corresponding to 420 to 460 of SEQ ID NO: 1. In some embodiments, the insertion site is between adjacent amino acids in the parental sequence corresponding to 444 and 445 of SEQ ID NO: 1. An exemplary embodiment is the AAV5 capsid disclosure as SEQ ID NO: 31.

In some embodiments, the recombinant adeno-associated virus (rAAV) virion disclosed herein comprise an AAV5 capsid protein, wherein the capsid protein comprises one or more substitutions selected from S651G, S651V, S651L, S651I, T578A, T578G, T578V, T578L, T578I, T582A, T582G, T582V, T582L, or T582I compared to a parental AAV5 capsid; and a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product.

In some embodiments, the recombinant adeno-associated virus (rAAV) virion disclosed herein comprise an AAV5 capsid protein, wherein the capsid protein comprises one or more substitutions selected from S651A, T578A, or T582A compared to a parental AAV5 capsid; and a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product.

The AAV5 capsid protein may comprise any two substitutions selected from S651A or S651V; T578A or T578V; or T582A or T582V—or all three of S651A or S651V; T578A or T578V; or T582A or T582V. The following combinations of mutations are expressly contemplated by the present disclosure:

-   -   a) T578G+S651G;     -   b) T578V+S651V;     -   c) T578L+S651L;     -   d) T578I+S651I;     -   e) T582A+S651A;     -   f) T582G+S651G;     -   g) T582V+S651V;     -   h) T582L+S651L;     -   i) T582I+S651I;     -   j) T578A+T582A+S651A;     -   k) T578G+T582G+S651G;     -   l) T578V+T582V+S651V;     -   m) T578L+T582L+S651L; and     -   n) T578I+T582I+S651I.

The AAV5 capsid protein may comprise any two substitutions selected from S651A, T578A, or T582A; or all three S651A, T578A, or T582A. For example, the AAV5 capsid protein may be any one of SEQ ID NOs 74-80, or a sequence at least 90%, 92%, 95%, 96%, 97%, 98%, 99%, or 100% identical thereto.

T578A, T582A, and/or S651A (SEQ ID NO: 73) MSFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAKTAPTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN NQGADGVGNASGDWHCDSTWMGDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV AYNVGGQMATNNQSST X APA X GTYNLQEIVPGSVWMERDVYLQGPIWAKIP ETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSF X DVPVSSFITQYS TGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRP IGTRYLTRPL, where X = A, G, V, S, or T T578A (SEQ ID NO: 74) MSFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAKTAPTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN NQGADGVGNASGDWHCDSTWMGDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV AYNVGGQMATNNQSST A APA T GTYNLQEIVPGSVWMERDVYLQGPIWAKIP ETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSF S DVPVSSFITQYS TGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRP IGTRYLTRPL T582A (SEQ ID NO: 75) MSFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAKTAPTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN NQGADGVGNASGDWHCDSTWMGDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV AYNVGGQMATNNQSST T APA A GTYNLQEIVPGSVWMERDVYLQGPIWAKIP ETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSF S DVPVSSFITQYS TGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRP IGTRYLTRPL S651A (SEQ ID NO: 76) MSFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAKTAPTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN NQGADGVGNASGDWHCDSTWMGDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV AYNVGGQMATNNQSST T APA T GTYNLQEIVPGSVWMERDVYLQGPIWAKIP ETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSF A DVPVSSFITQYS TGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRP IGTRYLTRPL T578A and T582A (SEQ ID NO: 77) MSFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAKTAPTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN NQGADGVGNASGDWHCDSTWMGDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV AYNVGGQMATNNQSST A APA A GTYNLQEIVPGSVWMERDVYLQGPIWAKIP ETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSF S DVPVSSFITQYS TGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRP IGTRYLTRPL T578A and S651A (SEQ ID NO: 78) MSFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAKTAPTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN NQGADGVGNASGDWHCDSTWMGDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV AYNVGGQMATNNQSST A APA T GTYNLQEIVPGSVWMERDVYLQGPIWAKIP ETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSF A DVPVSSFITQYS TGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRP IGTRYLTRPL T582A and S651A (SEQ ID NO: 79) MSFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAKTAPTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN NQGADGVGNASGDWHCDSTWMGDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV AYNVGGQMATNNQSST T APA A GTYNLQEIVPGSVWMERDVYLQGPIWAKIP ETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSF A DVPVSSFITQYS TGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRP IGTRYLTRPL T578A, T582A, and S651A (SEQ ID NO: 80) MSFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAKTAPTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN NQGADGVGNASGDWHCDSTWMGDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV AYNVGGQMATNNQSST A APA A GTYNLQEIVPGSVWMERDVYLQGPIWAKIP ETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSF A DVPVSSFITQYS TGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRP IGTRYLTRPL

In any of the foregoing sequences, the alanine substitution may instead be a substitutions to a valine (V), glycine (G), leucine (L), or isoleucine (I).

In some embodiments, one or more amino acid residues are conserved to the residue present in wild-type AAV5 capsid. For example, in some embodiments, T581 is conserved as a tyrosine (T), or semi-conserved as serine (S). By contrast, U.S. Pat. No. 10,046,016 teaches that infectivity of lung epithelial cells is increased by mutation by a T581A mutation.

Definitions

Unless the context indicates otherwise, the features of the invention can be used in any combination. Any feature or combination of features set forth can be excluded or omitted. Certain features of the invention, which are described in separate embodiments may also be provided in combination in a single embodiment. Features of the invention, which are described in a single embodiment may also be provided separately or in any suitable sub-combination. All combinations of the embodiments are disclosed herein as if each and every combination were individually disclosed. All sub-combinations of the embodiments and elements are disclosed herein as if every such sub-combination were individually disclosed.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The detailed description is divided into sections only for the reader's convenience and disclosure found in any section may be combined with that in another section. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, the exemplary methods and materials are now described. All publications mentioned herein are incorporated by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. Reference to a publication is not an admission that the publication is prior art.

The singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. For example, reference to “a recombinant AAV virion” includes a plurality of such virions and reference to “the cardiac cell” includes one or more cardiac cells.

The conjunction “and/or” means both “and” and “or,” and lists joined by “and/or” encompasses all possible combinations of one or more of the listed items.

The term “vector” refers to a macromolecule or complex of molecules comprising a polynucleotide or protein to be delivered to a cell.

“AAV” is an abbreviation for adeno-associated virus. The term covers all subtypes of AAV, except where a subtype is indicated, and to both naturally occurring and recombinant forms. The abbreviation “rAAV” refers to recombinant adeno-associated virus. “AAV” includes AAV or any subtype. “AAV5” refers to AAV subtype 5. The genomic sequences of various serotypes of AAV, as well as the sequences of the native inverted terminal repeats (ITRs), Rep proteins, and capsid subunits may be found in the literature or in public databases such as GenBank. See. e.g., GenBank Accession Numbers NC_002077 (AAV1), AF063497 (AAV1), NC_001401 (AAV2), AF043303 (AAV2), NC_001729 (AAV3), NC_001829 (AAV4), U89790 (AAV4), NC_006152 (AAV5), AF513851 (AAV7), AF513852(AAV8), and NC_006261 (AAV8). Publications describing AAV include Srivistava et al. (1983) J. Virol. 45:555; Chiorini et al. (1998) J. Virol. 71:6823; Chiorini et al. (1999) J. Virol. 73:1309; Bantel-Schaal et al. (1999) J. Virol. 73:939; Xiao et al. (1999) J. Virol. 73:3994; Muramatsu et al. (1996) Virol. 221:208; Shade et al. (1986) J. Virol. 58:921; Gao et al. (2002) Proc. Nat. Acad. Sci. USA 99: 11854; Moris et al. (2004) Virology 33:375-383; Int'l Pat. Publ Nos. WO2018/222503A1, WO2012/145601A2, WO2000/028061A2, WO1999/61601A2, and WO1998/11244A2; U.S. patent application Ser. Nos. 15/782,980 and 15/433,322; and U.S. Pat. Nos. 10,036,016, 9,790,472, 9,737,618, 9,434,928, 9,233,131, 8,906,675, 7,790,449, 7,906,111, 7,718,424, 7,259,151, 7,198,951, 7,105,345, 6,962,815, 6,984,517, and 6,156,303.

An “AAV vector” or “rAAV vector” as used in the art to refer either to the DNA packaged into in the rAAV virion or to the rAAV virion itself, depending on context. As used herein, unless otherwise apparent from context, rAAV vector refers to a nucleic acid (typically a plasmid) comprising a polynucleotide sequence capable of being packaged into an rAAV virion, but with the capsid or other proteins of the rAAV virion. Generally an rAAV vector comprises a heterologous polynucleotide sequence (i.e., a polynucleotide not of AAV origin) and one or two AAV inverted terminal repeat sequences (ITRs) flanking the heterologous polynucleotide sequence. Only one of the two ITRs may be packaged into the rAAV and yet infectivity of the resulting rAAV virion may be maintained. See Wu et al. (2010) Mol Ther. 18:80. An rAAV vector may be designed to generate either single-stranded (ssAAV) or self-complementary (scAAV). See McCarty D. (2008) Mo. Ther. 16:1648-1656; WO2001/11034; WO2001/92551; WO2010/129021.

An “rAAV virion” refers to an extracellular viral particle including at least one viral capsid protein (e.g. VP1) and an encapsidated rAAV vector (or fragment thereof), including the capsid proteins.

For brevity and clarity, the disclosure refers to “capsid protein” or “capsid proteins.” Those skilled in the art understand that such references refer to VP1, VP2, or VP3, or combinations of VP1, VP2, and VP3. As in wild-type AAV and most recombinant expression systems VP1, VP2, and VP3 are expressed from the same open reading frame, engineering of the sequence that encodes VP3 inevitably alters the sequences of the C-terminal domain of VP1 and VP2. One may also express the capsid proteins from different open reading frames, in which case the capsid of the resulting rAAV virion could contain a mixture of wild-type and engineered capsid proteins, and mixtures of different engineered capsid proteins.

The term “inverted terminal repeats” or “ITRs” as used herein refers to AAV viral cis-elements named so because of their symmetry. These elements are essential for efficient multiplication of an AAV genome. Without being bound by theory, it is believed that the minimal elements indispensable for ITR function are a Rep-binding site and a terminal resolution site plus a variable palindromic sequence allowing for hairpin formation. The disclosure contemplates that alternative means of generating an AAV genome may exist or may be prospectively developed to be compatible with the capsid proteins of the disclosure.

“Helper virus functions” refers to functions encoded in a helper virus genome which allow AAV replication and packaging.

“Packaging” refers to a series of intracellular events that result in the assembly of an rAAV virion including encapsidation of the rAAV vector. AAV “rep” and “cap” genes refer to polynucleotide sequences encoding replication and encapsidation proteins of adeno-associated virus. AAV rep and cap are referred to herein as AAV “packaging genes.” Packaging requires either a helper virus itself or, more commonly in recombinant systems, helper virus function supplied by a helper-free system (i.e. one or more helper plasmids).

A “helper virus” for AAV refers to a virus that allows AAV (e.g. wild-type AAV) to be replicated and packaged by a mammalian cell. The helper viruses may be an adenovirus, herpesvirus or poxvirus, such as vaccinia.

An “infectious” virion or viral particle is one that comprises a competently assembled viral capsid and is capable of delivering a polynucleotide component into a cell for which the virion is tropic. The term does not necessarily imply any replication capacity of the virus.

“Infectivity” refers to a measurement of the ability of a virion to inflect a cell. Infectivity can be expressed as the ratio of infectious viral particles to total viral particles. Infectivity is general determined with respect to a particular cell type. It can be measured both in vivo or in vitro. Methods of determining the ratio of infectious viral particle to total viral particle are known in the art. See. e.g., Grainger et al. (2005) Mol. Ther. 11:S337 (describing a TCID₅₀ infectious titer assay); and Zolotukhin et al. (1999) Gene Ther. 6:973.

The terms “parental capsid” or “parental sequence” refer to a reference sequence from which a particle capsid or sequence is derived. Unless otherwise specified, parental sequence refers to the sequence of the wild-type capsid protein of the same serotype as the engineered capsid protein.

A “replication-competent” virus (e.g. a replication-competent AAV) refers to a virus that is infectious, and is also capable of being replicated in an infected cell (i.e. in the presence of a helper virus or helper virus functions). In some embodiments, the rAAV virion of the disclosure comprises a genome that lacks the rep gene, or both the rep and cap genes, and therefore is replication incompetent.

The practice of the present disclosure will employ, unless otherwise indicated, conventional techniques of tissue culture, immunology, molecular biology, cell biology and recombinant DNA, which are within the skill of the art. See, e.g., Sambrook and Russell eds. (2001) Molecular Cloning: A Laboratory Manual, 3^(rd) edition; Ausubel et al. eds. (2007) Current Protocols in Molecular Biology; Methods in Enzymology (Academic Press, Inc., N.Y.); MacPherson et al. (1991) PCR 1: A Practical Approach (IRL Press at Oxford University Press); MacPherson et al. (1995) PCR 2: A Practical Approach; Harlow and Lane eds. (1999) Antibodies, A Laboratory Manual; Freshney (2005) Culture of Animal Cells: A Manual of Basic Technique, 5^(th) edition; Gait ed. (1984) Oligonucleotide Synthesis; U.S. Pat. No. 4,683,195; Hames and Higgins eds. (1984) Nucleic Acid Hybridization; Anderson (1999) Nucleic Acid Hybridization; Hames and Higgins eds. (1984) Transcription and Translation; IRL Press (1986) Immobilized Cells and Enzymes; Perbal (1984) A Practical Guide to Molecular Cloning; Miller and Calos eds. (1987) Gene Transfer Vectors for Mammalian Cells (Cold Spring Harbor Laboratory); Makrides ed. (2003) Gene Transfer and Expression in Mammalian Cells; Mayer and Walker eds. (1987) Immunochemical Methods in Cell and Molecular Biology (Academic Press, London); Herzenberg et al. eds (1996) Weir's Handbook of Experimental Immunology; Manipulating the Mouse Embryo: A Laboratory Manual, 3^(rd) edition (2002) Cold Spring Harbor Laboratory Press; Sohail (2004) Gene Silencing by RNA Interference: Technology and Application (CRC Press); and Sell (2013) Stem Cells Handbook.

The terms “nucleic acid” and “polynucleotide” are used interchangeably and refer to a polymeric form of nucleotides of any length, either deoxyribonucleotides or ribonucleotides, or analogs thereof. Non-limiting examples of polynucleotides include linear and circular nucleic acids, messenger RNA (mRNA), cDNA, recombinant polynucleotides, vectors, probes, and primers. Unless otherwise specified or required, any embodiment of the invention described herein that is a polynucleotide encompasses both the double-stranded form and each of two complementary single-stranded forms known or predicted to make up the double-stranded form.

The terms “polypeptide” and “protein,” are used interchangeably herein and refer to a polymeric form of amino acids of any length, which can include genetically coded and non-genetically coded amino acids, chemically or biochemically modified or derivatized amino acids, and polypeptides having modified peptide backbones. The terms also encompass an amino acid polymer that has been modified; for example, disulfide bond formation, glycosylation, lipidation, phosphorylation, or conjugation with a labeling component.

The term “peptide” refers to a short polypeptide, e.g. a peptide having between about 4 and 30 amino acid residues.

The term “isolated” means separated from constituents, cellular and otherwise, in which the virion, cell, tissue, polynucleotide, peptide, polypeptide, or protein is normally associated in nature. For example, an isolated cell is a cell that is separated form tissue or cells of dissimilar phenotype or genotype.

As used herein, “sequence identity” or “identity” refers to the percentage of number of amino acids that are identical between a sequence of interest and a reference sequence. Generally identity is determined by aligning the the sequence of interest to the reference sequence, determining the number of amino acids that are identical between the aligned sequences, dividing that number by the total number of amino acids in the reference sequence, and multiplying the result by 100 to yield a percentage. Sequences can be aligned using various computer programs, such BLAST, available at ncbi.nlm.nih.gov. Other techniques for alignment are described in Methods in Enzymology, vol. 266: Computer Methods for Macromolecular Sequence Analysis (1996); and Meth. Mol. Biol. 70: 173-187 (1997); J. Mol. Biol. 48: 44. Skill artisans are capable of choosing an appropriate alignment method depending on various factors including sequence length, divergence, and the presence of absence of insertions or deletions with respect to the reference sequence.

“Recombinant,” as applied to a polynucleotide means that the polynucleotide is the product of various combinations of cloning, restriction or ligation steps, and other procedures that result in a construct that is distinct from a polynucleotide found in nature, or that the polynucleotide is assembled from synthetic oligonucleotides. A “recombinant” protein is a protein produced from a recombinant polypeptide. A recombinant virion is a virion that comprises a recombinant polynucleotide and/or a recombinant protein, e.g. a recombinant capsid protein.

A “gene” refers to a polynucleotide containing at least one open reading frame that is capable of encoding a particular protein after being transcribed and translated. A “gene product” is a molecule resulting from expression of a particular gene. Gene products may include, without limitation, a polypeptide, a protein, an aptamer, an interfering RNA, or an mRNA. Gene-editing systems (e.g. a CRISPR/Cas system) may be described as one gene product or as the several gene products required to make the system (e.g. a Cas protein and a guide RNA).

A “short hairpin RNA,” or shRNA, is a polynucleotide construct used to express an siRNA.

A “control element” or “control sequence” is a nucleotide sequence involved in an interaction of molecules that contributes to the functional regulation of a polynucleotide, including replication, duplication, transcription, splicing, translation, or degradation of the polynucleotide. The regulation may affect the frequency, speed, or specificity of the process, and may be enhancing or inhibitory in nature. Control elements include transcriptional regulatory sequences such as promoters and/or enhancers.

A “promoter” is a DNA sequence capable under certain conditions of binding RNA polymerase and initiating transcription of a coding region usually located downstream (in the 3′ direction) from the promoter. The term “tissue-specific promoter” as used herein refers to a promoter that is operable in cells of a particular organ or tissue, such as the cardiac tissue.

“Operatively linked” or “operably linked” refers to a juxtaposition of genetic elements, wherein the elements are in a relationship permitting them to operate in the expected manner. For instance, a promoter is operatively linked to a coding region if the promoter helps initiate transcription of the coding sequence. There may be intervening residues between the promoter and coding region so long as this functional relationship is maintained.

An “expression vector” is a vector comprising a coding sequence which encodes a gene product of interest used to effect the expression of the gene product in target cells. An expression vector comprises control elements operatively linked to the coding sequence to facilitate expression of the gene product.

The term “expression cassette” refers to a heterologous polynucleotide comprising a coding sequence which encodes a gene product of interest used to effect the expression of the gene product in target cells. Unless otherwise specified, the expression cassette of an AAV vector include the polynucleotides between (and not including) the ITRs.

The term “gene delivery” or “gene transfer” as used herein refers to methods or systems for reliably inserting foreign nucleic acid sequences, e.g., DNA, into host cells. Such methods can result in transient expression of non-integrated transferred DNA, extrachromosomal replication and expression of transferred replicons (e.g., episomes), or integration of transferred genetic material into the genomic DNA of host cells.

“Heterologous” means derived from a genotypically distinct entity from that of the rest of the entity to which it is being compared. For example, a polynucleotide introduced by genetic engineering techniques into a plasmid or vector derived from a different species is a heterologous polynucleotide. A promoter removed from its native coding sequence and operatively linked to a coding sequence with which it is not naturally found linked is a heterologous promoter. Thus, for example, an rAAV that includes a heterologous nucleic acid is an rAAV that includes a nucleic acid not normally included in a naturally-occurring AAV.

The terms “genetic alteration” and “genetic modification” (and grammatical variants thereof), are used interchangeably herein to refer to a process wherein a genetic element (e.g., a polynucleotide) is introduced into a cell other than by mitosis or meiosis. The element may be heterologous to the cell, or it may be an additional copy or improved version of an element already present in the cell. Genetic alteration may be effected, for example, by transfecting a cell with a recombinant plasmid or other polynucleotide through any process known in the art, such as electroporation, calcium phosphate precipitation, or contacting with a polynucleotide-liposome complex. Genetic alteration may also be effected, for example, by transduction or infection with a vector.

A cell is said to be “stably” altered, transduced, genetically modified, or transformed with a polynucleotide sequence if the sequence is available to perform its function during extended culture of the cell in vitro. Generally, such a cell is “heritably” altered (genetically modified) in that a genetic alteration is introduced which is also inheritable by progeny of the altered cell.

The term “transfection” is as used herein refers to the uptake of an exogenous nucleic acid molecule by a cell. A cell has been “transfected” when exogenous nucleic acid has been introduced inside the cell membrane. A number of transfection techniques are generally known in the art. See. e.g., Graham et al. (1973) Virology, 52:456, Sambrook et al. (1989) Molecular Cloning, a laboratory manual, Cold Spring Harbor Laboratories, New York, Davis et al. (1986) Basic Methods in Molecular Biology, Elsevier, and Chu et al. (1981) Gene 13:197. Such techniques can be used to introduce one or more exogenous nucleic acid molecules into suitable host cells.

The term “transduction” is as used herein refers to the transfer of an exogenous nucleic acid into a cell by a recombinant virion, in contrast to “infection” by a wild-type virion. When infection is used with respect to a recombinant virion, the terms “transduction” and “infectious” are synonymous, and therefore “infectivity” and “transduction efficiency” are equivalent and can be determined using similar methods.

Unless otherwise specified, all medical terminology is given the ordinary meaning of the term used by medical professional as, for example, in Harrison's Principles of Internal Medicine, 15ed., which is incorporated by reference in its entirety for all purposes, in particular the chapters on cardiac or cardiovascular diseases, disorders, conditions, and dysfunctions.

“Treatment,” “treating,” and “treat” are defined as acting upon a disease, disorder, or condition with an agent to reduce or ameliorate harmful or any other undesired effects of the disease, disorder, or condition and/or its symptoms.

“Administration,” “administering” and the like, when used in connection with a composition of the invention refer both to direct administration (administration to a subject by a medical professional or by self-administration by the subject) and/or to indirect administration (prescribing a composition to a patient). Typically, an effective amount is administered, which amount can be determined by one of skill in the art. Any method of administration may be used. Administration to a subject can be achieved by, for example, intravenous, intrarterial, intramuscular, intravascular, or intramyocardial delivery.

As used herein the term “effective amount” and the like in reference to an amount of a composition refers to an amount that is sufficient to induce a desired physiologic outcome (e.g., reprogramming of a cell or treatment of a disease). An effective amount can be administered in one or more administrations, applications or dosages. Such delivery is dependent on a number of variables including the time period which the individual dosage unit is to be used, the bioavailability of the composition, the route of administration, etc. It is understood, however, that specific amounts of the compositions (e.g., rAAV virions) for any particular subject depends upon a variety of factors including the activity of the specific agent employed, the age, body weight, general health, sex, and diet of the subject, the time of administration, the rate of excretion, the composition combination, severity of the particular disease being treated and form of administration.

The terms “individual,” “subject,” and “patient” are used interchangeably herein, and refer to a mammal, including, but not limited to, human and non-human primates (e.g., simians); mammalian sport animals (e.g., horses); mammalian farm animals (e.g., sheep, goats, etc.); mammalian pets (e.g., dogs, cats, etc.); and rodents (e.g., mice, rats, etc.).

The terms “cardiac pathology” or “cardiac dysfunction” are used interchangeably and refer to any impairment in the heart's pumping function. This includes, for example, impairments in contractility, impairments in ability to relax (sometimes referred to as diastolic dysfunction), abnormal or improper functioning of the heart's valves, diseases of the heart muscle (sometimes referred to as cardiomyopathies), diseases such as angina pectoris, myocardial ischemia and/or infarction characterized by inadequate blood supply to the heart muscle, infiltrative diseases such as amyloidosis and hemochromatosis, global or regional hypertrophy (such as may occur in some kinds of cardiomyopathy or systemic hypertension), and abnormal communications between chambers of the heart.

As used herein, the term “cardiomyopathy” refers to any disease or dysfunction that affects myocardium directly. The etiology of the disease or disorder may be, for example, inflammatory, metabolic, toxic, infiltrative, fibroplastic, hematological, genetic, or unknown in origin. Two fundamental forms are recognized (1) a primary type, consisting of heart muscle disease of unknown cause; and (2) a secondary type, consisting of myocardial disease of known cause or associated with a disease involving other organ systems. “Specific cardiomyopathy” refers to heart diseases associated with certain systemic or cardiac disorders; examples include hypertensive and metabolic cardiomyopathy. The cardiomyopathies include dilated cardiomyopathy (DCM), a disorder in which left and/or right ventricular systolic pump function is impaired, leading to progressive cardiac enlargement; hypertrophic cardiomyopathy, characterized by left ventricular hypertrophy without oblivious causes such as hypertension or aortic stenosis; and restrictive cardiomyopathy, characterized by abnormal diastolic function and excessively rigid ventricular walls that impede ventricular filling. Cardiomyopathies also include left ventricular non-compaction, arrhythmogenic right ventricular cardiomyopathy, and arrhythmogenic right ventricular dysplasia.

“Heart failure” referees to the pathological state in which an abnormality of cardiac function is responsible for failure of the hear to pump blood at a rate commensurate with the requirements of the metabolizing tissues and/or allows the heart to do so only from an abnormally elevated diastolic volume. Heart failure includes systolic and diastolic failure. Patient with heart failure are classified into those with low cardiac output (typically secondary to ischemic heart disease, hypertension, dilated cardiomyopathy, and/or valvular or pericardial disease) and those with elevated cardiac output (typically due to hyperthyroidism, anemia, pregnancy, arteriovenous fistulas, beriberi, and Paget's disease). Heart failure includes heart failure with reduced ejection fraction (HFrEF) and heart failure with preserved ejection fraction (HFpEF).

The phrase “pharmaceutically acceptable” is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.

The term “purified” as used herein refers to material that has been isolated under conditions that reduce or eliminate the presence of unrelated materials, i.e. impurities, including native materials from which the material is obtained. For example, purified rAAV vector DNA is preferably substantially free of cell or culture components, including tissue culture components, contaminants, and the like.

The terms “regenerate,” “regeneration” and the like as used herein in the context of injured cardiac tissue shall be given their ordinary meanings and shall also refer to the process of growing and/or developing new cardiac tissue in a heart or cardiac tissue that has been injured, for example, injured due to ischemia, infarction, reperfusion, or other disease. In some embodiments, cardiac tissue regeneration comprises generation of cardiomyocytes.

The term “therapeutic gene” as used herein refers to a gene that, when expressed, confers a beneficial effect on the cell or tissue in which it is present, or on a mammal in which the gene is expressed. Examples of beneficial effects include amelioration of a sign or symptom of a condition or disease, prevention or inhibition of a condition or disease, or conferral of a desired characteristic. Therapeutic genes include genes that partially or wholly correct a genetic deficiency in a cell or mammal.

As used herein, the term “functional cardiomyocyte” refers to a differentiated cardiomyocyte that is able to send or receive electrical signals. In some embodiments, a cardiomyocyte is said to be a functional cardiomyocyte if it exhibits electrophysiological properties such as action potentials and/or Ca²⁺ transients.

As used herein, a “differentiated non-cardiac cell” can refer to a cell that is not able to differentiate into all cell types of an adult organism (i.e., is not a pluripotent cell), and which is of a cellular lineage other than a cardiac lineage (e.g., a neuronal lineage or a connective tissue lineage). Differentiated cells include, but are not limited to, multipotent cells, oligopotent cells, unipotent cells, progenitor cells, and terminally differentiated cells. In particular embodiments, a less potent cell is considered “differentiated” in reference to a more potent cell.

A “somatic cell” is a cell forming the body of an organism. Somatic cells include cells making up organs, skin, blood, bones and connective tissue in an organism, but not germ cells.

As used herein, the term “totipotent” means the ability of a cell to form all cell lineages of an organism. For example, in mammals, only the zygote and the first cleavage stage blastomeres are totipotent.

As used herein, the term “pluripotent” means the ability of a cell to form all lineages of the body or soma. For example, embryonic stem cells are a type of pluripotent stem cells that are able to form cells from each of the three germs layers, the ectoderm, the mesoderm, and the endoderm. Pluripotent cells can be recognized by their expression of markers such as Nanog and Rex1.

As used herein, the term “multipotent” refers to the ability of an adult stem cell to form multiple cell types of one lineage. For example, hematopoietic stem cells are capable of forming all cells of the blood cell lineage, e.g., lymphoid and myeloid cells.

As used herein, the term “oligopotent” refers to the ability of an adult stem cell to differentiate into only a few different cell types. For example, lymphoid or myeloid stem cells are capable of forming cells of either the lymphoid or myeloid lineages, respectively.

As used herein, the term “unipotent” means the ability of a cell to form a single cell type. For example, spermatogonial stem cells are only capable of forming sperm cells.

As used herein, the term “reprogramming” or “transdifferentiation” refers to the generation of a cell of a certain lineage (e.g., a cardiac cell) from a different type of cell (e.g., a fibroblast cell) without an intermediate process of de-differentiating the cell into a cell exhibiting plurinpotent stem cell characteristics.

As used herein the term “cardiac cell” refers to any cell present in the heart that provides a cardiac function, such as heart contraction or blood supply, or otherwise serves to maintain the structure of the heart. Cardiac cells as used herein encompass cells that exist in the epicardium, myocardium or endocardium of the heart. Cardiac cells also include, for example, cardiac muscle cells or cardiomyocytes, and cells of the cardiac vasculatures, such as cells of a coronary artery or vein. Other non-limiting examples of cardiac cells include epithelial cells, endothelial cells, fibroblasts, cardiac stem or progenitor cells, cardiac conducting cells and cardiac pacemaking cells that constitute the cardiac muscle, blood vessels and cardiac cell supporting structure. Cardiac cells may be derived from stem cells, including, for example, embryonic stem cells or induced pluripotent stem cells.

The term “cardiomyocyte” or “cardiomyocytes” as used herein refers to sarcomere-containing striated muscle cells, naturally found in the mammalian heart, as opposed to skeletal muscle cells. Cardiomyocytes are characterized by the expression of specialized molecules e.g., proteins like myosin heavy chain, myosin light chain, cardiac α-actinin. The term “cardiomyocyte” as used herein is an umbrella term comprising any cardiomyocyte subpopulation or cardiomyocyte subtype, e.g., atrial, ventricular and pacemaker cardiomyocytes.

The term “cardiomyocyte-like cells” is intended to mean cells sharing features with cardiomyocytes, but which may not share all features. For example, a cardiomyocyte-like cell may differ from a cardiomyocyte in expression of certain cardiac genes.

The term “culture” or “cell culture” means the maintenance of cells in an artificial, in vitro environment. A “cell culture system” is used herein to refer to culture conditions in which a population of cells may be grown as monolayers or in suspension. “Culture medium” is used herein to refer to a nutrient solution for the culturing, growth, or proliferation of cells. Culture medium may be characterized by functional properties such as, but not limited to, the ability to maintain cells in a particular state (e.g., a pluripotent state, a quiescent state, etc.), to mature cells—in some instances, specifically, to promote the differentiation of progenitor cells into cells of a particular lineage (e.g., a cardiomyocyte).

As used herein, the term “expression” or “express” refers to the process by which polynucleotides are transcribed into mRNA and/or the process by which the transcribed mRNA is subsequently being translated into peptides, polypeptides, or proteins. If the polynucleotide is derived from genomic DNA, expression may include splicing of the mRNA in a eukaryotic cell. The expression level of a gene may be determined by measuring the amount of mRNA or protein in a cell or tissue sample.

The term “induced cardiomyocyte” or the abbreviation “iCM” refers to a non-cardiomyocyte (and its progeny) that has been transformed into a cardiomyocyte (and/or cardiomyocyte-like cell). The methods of the present disclosure can be used in conjunction with any methods now known or later discovered for generating induced cardiomyocytes, for example, to enhance other techniques.

The term “induced pluripotent stem cell-derived cardiomyocytes” as used herein refers to human induced pluripotent stem cells that have been differentiated into cardiomyocyte-like cells. Exemplary methods for prepared iPS-CM cells are provided by Karakikes et al. Circ Res. 2015 Jun. 19; 117(1): 80-88.

The terms “human cardiac fibroblast” and “mouse cardiac fibroblast” as used herein refer to primary cell isolated from the ventricles of the adult heart of a human or mouse, respectively, and maintain in culture ex vivo.

The term “non-cardiomyocyte” as used herein refers to any cell or population of cells in a cell preparation not fulfilling the criteria of a “cardiomyocyte” as defined and used herein. Non-limiting examples of non-cardiomyocytes include somatic cells, cardiac fibroblasts, non-cardiac fibroblasts, cardiac progenitor cells, and stem cells.

As used herein “reprogramming” includes transdifferentiation, dedifferentiation and the like.

As used herein, the term “reprogramming efficiency” refers to the number of cells in a sample that are successfully reprogrammed to cardiomyocytes relative to the total number of cells in the sample.

The term “reprogramming factor” as used herein includes a factor that is introduced for expression in a cell to assist in the reprogramming of the cell from one cell type into another.

For example, a reprogramming factor may include a transcription factor that, in combination with other transcription factors and/or small molecules, is capable of reprogramming a cardiac fibroblast into an induced cardiomyocyte. Unless otherwise clear from context, a reprogramming factor refers to a polypeptide that can be encoded by an AAV-delivered polynucleotide. Reprogramming factors may also include small molecules.

The term “stem cells” refer to cells that have the capacity to self-renew and to generate differentiated progeny. The term “pluripotent stem cells” refers to stem cells that can give rise to cells of all three germ layers (endoderm, mesoderm and ectoderm), but do not have the capacity to give rise to a complete organism.

As used herein, the term “equivalents thereof” in reference to a polypeptide or nucleic acid sequence refers to a polypeptide or nucleic acid that differs from a reference polypeptide or nucleic acid sequence, but retains essential properties (e.g., biological activity). A typical variant of a polynucleotide differs in nucleotide sequence from another, reference polynucleotide. Changes in the nucleotide sequence of the variant may or may not alter the amino acid sequence of a polypeptide encoded by the reference polynucleotide. Nucleotide changes may result in amino acid substitutions, deletions, additions, fusions and truncations in the polypeptide encoded by the reference sequence. Generally, differences are limited so that the sequences of the reference polypeptide and the variant are closely similar overall and, in many regions, identical.

As used herein, the term “progenitor cell” refers to a cell that is committed to differentiate into a specific type of cell or to form a specific type of tissue. A progenitor cell, like a stem cell, can further differentiate into one or more kinds of cells, but is more mature than a stem cell such that it has a more limited/restricted differentiation capacity.

The term “genetic modification” refers to a permanent or transient genetic change induced in a cell following introduction of new nucleic acid (i.e., nucleic acid exogenous to the cell). Genetic change can be accomplished by incorporation of the new nucleic acid into the genome of the cardiac cell, or by transient or stable maintenance of the new nucleic acid as an extrachromosomal element. Where the cell is a eukaryotic cell, a permanent genetic change can be achieved by introduction of the nucleic acid into the genome of the cell. Suitable methods of genetic modification include viral infection, transfection, conjugation, protoplast fusion, electroporation, particle gun technology, calcium phosphate precipitation, direct microinjection, and the like.

The term “stem cells” refer to cells that have the capacity to self-renew and to generate differentiated progeny. The term “pluripotent stem cells” refers to stem cells that can give rise to cells of all three germ layers (endoderm, mesoderm and ectoderm), but do not have the capacity to give rise to a complete organism. In some embodiments, the compositions for inducing cardiomycocyte phenotype can be used on a population of cells to induce reprogramming. In other embodiments, the compositions induce a cardiomycocyte phenotype.

The term “induced pluripotent stem cells” shall be given its ordinary meaning and shall also refer to differentiated mammalian somatic cells (e.g., adult somatic cells, such as skin) that have been reprogrammed to exhibit at least one characteristic of pluripotency. See, for example, Takahashi et al. (2007) Cell 131(5):861-872, Kim et al. (2011) Proc. Natl. Acad. Sci. 108(19): 7838-7843, Sell (2013) Stem Cells Handbook.

The term “transduction efficiency” refers to the percentage of cells transduced with at least one AAV genome. For example, if 1×10⁶ cells are exposed to a virus and 0.5×10⁶ cells are determined to contain at least one copy of the AAV genome, then the transduction efficiency is 50%. An illustrative method for determining transduction efficiency is flow cytometry. For example, the percentage of GFP+ cells is a measure of transduction efficiency when the AAV genome comprises a polynucleotide encoding green fluorescence protein (GFP).

The term “selectivity” refers to the ratio of transduction efficiency for one cell type over another, or over all other cells types.

The term “infectivity” refers to the ability of an AAV virion to infect a cell, in particularly an in vivo cell. Infectivity therefore is a function of, at least, biodistribution and neutralizing antibody escape.

Unless stated otherwise, the abbreviations used throughout the specification have the following meanings: AAV, adeno-associated virus, rAAV, recombinant adeno-associated virus; AHCF, adult human cardiac fibroblast; APCF, adult pig cardiac fibroblast, a-MHC-GFP; alpha-myosin heavy chain green fluorescence protein; CF, cardiac fibroblast; cm, centimeter; CO, cardiac output; EF, ejection fraction; FACS, fluorescence activated cell sorting; GFP, green fluorescence protein; GMT, Gata4, Mef2c and Tbx5; GMTc, Gata4, Mef2c, Tbx5, TGF-βi, WNTi; GO, gene ontology; hCF, human cardiac fibroblast; iCM, induced cardiomyocyte; kg, killigram; μg, microgram; pd, microliter; mg, milligram; ml, milliliter; MI, myocardial infarction; msec, millisecond; min, minute; MyAMT, Myocardin, Ascl1, Mef2c and Tbx5; MyA, Myocardin and Ascl1; MyMT, Myocardin, Mef2c and Tbx5; MyMTc, Myocardin, Mef2c, Tbx5, TGF-βi, WNTi; MRI, magnetic resonance imaging; PBS, phosphate buffered saline; PBST, phosphate buffered saline, triton; PFA, paraformaldehyde; qPCR, quantitative polymerase chain reaction; qRT-PCR, quantitative reverse transcriptase polymerase chain reaction; RNA, ribonucleic acid; RNA-seq, RNA sequencing; RT-PCR, reverse transcriptase polymerase chain reaction; sec, second; SV, stroke volume; TGF-β, transforming growth factor beta; TGF-βi, transforming growth factor beta inhibitor; WNT, wingless-Int; WNTi, wingless-Int inhibitor; YFP, yellow fluorescence protein; 4F, Gata4, Mef2c, TBX5, and Myocardin; 4Fc, Gata4, Mef2c, TBX5, and Myocardin+TGF-βi and WNTi; 7F, Gata4, Mef2c, and Tbx5, Essrg, Myocardin, Zfpm2, and Mesp1; 7Fc, Gata4, Mef2c, and Tbx5, Essrg, Myocardin, Zfpm2, and Mesp1+TGF-0 and WNTi.

EMBODIMENTS AND VANATIONS

Compositions

Efforts to identify capsid variants with properties useful for gene therapy have included shuffling the DNA of AAV2 and AAV5 cap genes as described in U.S. Pat. No. 9,233,131; as well as directed evolution as described in Int'l Pat. Appl. Nos.

WO2012/145601A2 and WO2018/222503A1. The disclosures of these documents are incorporated here for all purposes, and particularly for the methods of making and using AAV virions and for the polynucleotide sequences and gene products therein disclosed, as well as for the combinations of transcription factors useful in treating cardiac diseases or disorders.

The AAV capsid is encoded by the cap gene of AAV, which is also termed the right open-reading frame (ORF) (in contrast to the left ORF, rep). The structures of representative AAV capsids are described in various publications including Xie et al. (2002)Proc. Natl. Acad. Sci USA 99:10405-1040 (AAV2); Govindasamy et al. (2006) J. Virol. 80:11556-11570 (AAV4); Nam et a. (2007) J. Virol. 81:12260-12271 (AAV8) and Govindasamy et al. (2013)J. Virol. 87:11187-11199 (AAV5).

The AAV capsid contain 60 copies (in total) of three viral proteins (VPs), VP1, VP2, and VP3, in a predicted ratio of 1:1:10, arranged with T=1 icosahedral symmetry. The three VPs are translated from the same mRNA, with VP1 containing a unique N-terminal domain in addition to the entire VP2 sequence at its C-terminal region. VP2 contains an extra N-terminal sequence in addition to VP3 at its C terminus. In most crystal structures, only the C-terminal polypeptide sequence common to all the capsid proteins (˜530 amino acids) is observed. The N-terminal unique region of VP1, the VP1-VP2 overlapping region, and the first 14 to 16 N-terminal residues of VP3 are thought to be primarily disordered. Cryo-electron microscopy and image reconstruction data suggest that in intact AAV capsids, the N-terminal regions of the VP1 and VP2 proteins are located inside the capsid and are inaccessible for receptor and antibody binding. Thus, receptor attachment and transduction phenotypes are, generally, determined by the amino acid sequences within the common C-terminal domain of VP1, VP2 and VP3

In some embodiments, the one or more amino acid insertions, substitutions, or deletions is/are in the GH loop, or loop IV, of the AAV capsid protein, e.g., in a solvent-accessible portion of the GH loop, or loop IV, of the AAV capsid protein. For the GH loop/loop IV of AAV capsid, see. e.g., van Vliet et al. (2006) Mol. Ther. 14:809; Padron et al. (2005) Virol. 79:5047; and Shen et al. (2007)Mol. Ther. 15: 1955. In some embodiments, a “parental” AAV capsid protein is a wild-type AAV5 capsid protein. In some embodiments, a “parental” AAV capsid protein is a chimeric AAV capsid protein. Amino acid sequences of various AAV capsid proteins are known in the art. See, e.g., GenBank Accession No. NP_049542 for AAV1; GenBank Accession No. NP_044927 for AAV4; GenBank Accession No. AAD13756 for AAV5; GenBank Accession No. AAB95450 for AAV6; GenBank Accession No. YP_077178 for AAV7; GenBank Accession No. YP_077180 for AAV 8; GenBank Accession No. AAS99264 for AAV9 and GenBank Accession No. AAT46337 for AAV10. See, e.g., Santiago-Ortiz et al. (2015) Gene Ther. 22:934 for a predicted ancestral AAV capsid.

Adeno-associated virus (AAV) is a replication-deficient parvovirus, the single-stranded DNA genome of which is about 4.7 kb in length including two 145 nucleotide inverted terminal repeat (ITRs). There are multiple serotypes of AAV. The nucleotide sequences of the genomes of the AAV serotypes are known. For example, the AAV5 genome is provided in GenBank Accession No. AF085716. The life cycle and genetics of AAV are reviewed in Muzyczka, Current Topics in Microbiology and Immunology, 158: 97-129 (1992). Production of pseudotyped rAAV is disclosed in, for example, WO 01/83692. Other types of rAAV variants, for example rAAV with capsid mutations, are also contemplated. See, for example, Marsic et al., Molecular Therapy, 22(11): 1900-1909 (2014). Illustrative AAV vectors are provided in U.S. Pat. No. 7,105,345; U.S. Ser. No. 15/782,980; U.S. Pat. Nos. 7,259,151; 6,962,815; 7,718,424; 6,984,517; 7,718,424; 6,156,303; 8,524,446; 7,790,449; 7,906,111; 9,737,618; U.S. application Ser. No. 15/433,322; U.S. Pat. No. 7,198,951, each of which is incorporated by reference in its entirety for all purposes.

The rAAV virions of the disclosure comprise a heterologous nucleic acid comprising a nucleotide sequence encoding one or more gene product. The gene product(s) may be either a polypeptide or an RNA, or both. When the gene product is a polypeptide, the nucleotide sequence encodes a messenger RNA, optionally with one or more introns, which is translated into the gene product polypeptide. The nucleotide sequence may encode one, two, three, or more gene products (though the number is limited by the packaging capacity of the rAAV virion, typically about 5.2 kb). The gene products may be operatively linked to one promoter (for a single transcriptional unit) or more than one. Multiple gene products may also be produced using internal ribosome entry signal (IRES) or a self-cleaving peptide (e.g., a 2A peptide).

In some embodiments, the gene product is a polypeptide. In some embodiments, the polypeptide gene product is a polypeptide that induces reprogramming of a cardiac fibroblast, to generate an induced cardiomyocyte-like cell (iCM). In some embodiments, the polypeptide gene product is a polypeptide that enhances the function of a cardiac cell. In some embodiments, the polypeptide gene product is a polypeptide that provides a function that is missing or defective in the cardiac cell. In some embodiments, the polypeptide gene product is a genome-editing endonuclease.

In some embodiments, the gene product comprises a fusion protein that is fused to a heterologous polypeptide. In some embodiments, the gene product comprises a genome editing nuclease fused to an amino acid sequence that provides for subcellular localization, i.e., the fusion partner is a subcellular localization sequence (e.g., one or more nuclear localization signals (NLSs) for targeting to the nucleus, two or more NLSs, three or more NLSs, etc.).

In general, a viral vector is produced by introducing a viral DNA or RNA construct into a “producer cell” or “packaging cell” line. Packaging cell lines include but are not limited to any easily-transfectable cell line. Packaging cell lines can be based on HEK291, 293T cells, NIH3T3, COS, HeLa or Sf9 cell lines. Examples of packaging cell lines include but are not limited to: Sf9 (ATCC® CRL-1711™). Exemplary packing cell lines and methods for generating rAAV virions are provided by Int'l Pat. Pub. Nos. WO2017075627, WO2015/031686, WO2013/063379, WO2011/020710, WO2009/104964, WO2008/024998, WO2003/042361, and WO1995/013392; U.S. Pat. Nos. U.S. Pat. No. 9,441,206B2, U.S. Pat. Nos. 8,679,837, and 7,091,029B2.

In some embodiments, the gene product is a functional cardiac protein. In some embodiments, the gene product is a genome-editing endonuclease (optionally with a guide RNA, single-guide RNA, and/or repair template) that replaces or repairs a non-functional cardiac protein into a functional cardiac protein. Functional cardiac proteins include, but are not limited to cardiac troponin T; a cardiac sarcomeric protein; β-myosin heavy chain; myosin ventricular essential light chain 1; myosin ventricular regulatory light chain 2; cardiac a-actin; a-tropomyosin; cardiac troponin I; cardiac myosin binding protein C; four-and-a-half LIM protein 1; titin; 5′-AMP-activated protein kinase subunit gamma-2; troponin I type 3, myosin light chain 2, actin alpha cardiac muscle 1; cardiac LIM protein; caveolin 3 (CAV3); galactosidase alpha (GLA); lysosomal-associated membrane protein 2 (LAMP2); mitochondrial transfer RNA glycine (MTTG); mitochondrial transfer RNA isoleucine (MTTI); mitochondrial transfer RNA lysine (MTTK); mitochondrial transfer RNA glutamine (MTTQ); myosin light chain 3 (MYL3); troponin C (TNNC1); transthyretin (TTR); sarcoendoplasmic reticulum calcium-ATPase 2a (SERCA2a); stromal-derived factor-1 (SDF-1); adenylate cyclase-6 (AC6); beta-ARKct (β-adrenergic receptor kinase C terminus); fibroblast growth factor (FGF); platelet-derived growth factor (PDGF); vascular endothelial growth factor (VEGF); hepatocyte growth factor; hypoxia inducible growth factor; thymosin beta 4 (TMSB4X); nitric oxide synthase-3 (NOS3); unocartin 3 (UCN3); melusin; apoplipoprotein-E (ApoE); superoxide dismutase (SOD); and S100A1 (a small calcium binding protein; see, e.g., Ritterhoff and Most (2012) Gene Ther. 19:613; Kraus et al. (2009) Mol. Cell. Cardiol. 47:445).

In some embodiments, the gene product is a gene product whose expression complements a defect in a gene responsible for a genetic disorder. The disclosure provides rAAV virions comprising a polynucleotide encoding one or more of the following—e.g., for use, without limitation, in the disorder indicated in parentheses, or for other disorders caused by each: TAZ (Barth syndrome); FXN (Freidrich's Ataxia); CASQ2 (CPVT); FBN1 (Marfan); RAF1 and SOSis (Noonan); SCN5A (Brugada); KCNQ1 and KCNH2s (Long QT Syndrome); DMPK (Myotonic Dystrophy 1); LMNA (Limb Girdle Dystrophy Type 1B); JUP (Naxos); TGFBR2 (Loeys-Dietz); EMD (X-Linked EDMD); and ELN (SV Aortic Stenosis). In some embodiments, the rAAV virion comprises a polynucleotide encording one or more of cardiac troponin T (TNNT2); BAG family molecular chaperone regulator 3 (BAG3); myosin heavy chain (MYH7); tropomyosin 1 (TPM1); myosin binding protein C (MYBPC3); 5′-AMP-activated protein kinase subunit gamma-2 (PRKAG2); troponin I type 3 (TNNI3); titin (TTN); myosin, light chain 2(MYL2); actin, alpha cardiac muscle 1 (ACTC1); potassium voltage-gated channel, KQT-like subfamily, member 1 (KCNQ1); plakophilin 2 (PKP2); myocyte enhancer factor 2c (MEF2C); and cardiac LIM protein (CSRP3).

In some embodiments, the gene products of the disclosure are polypeptide reprogramming factors. Reprogramming factors are desirable as means to convert one cell type into another. Non-cardiomyocytes cells can be differentiated into cardiomyocytes cells in vitro or in vivo using any method available to one of skill in the art. For example, see methods described in Ieda et al. (2010) Cell 142:375-386; Christoforou et al. (2013) PLoS ONE 8:e63577; Addis et al. (2013) J. Mol. Cell Cardiol. 60:97-106; Jayawardena et al. (2012) Circ. Res. 110: 1465-1473; Nam Y et al. (2003) PNAS USA 110:5588-5593; Wada R et al. (2013) PNAS USA 110: 12667-12672; and Fu J et al. (2013) Stem Cell Reports 1:235-247.

In cardiac context, the reprogramming factors may be capable of converting a cardiac fibroblast to a cardiac myocyte either directly or through an intermediate cell type. In particular, direct regramming is possible, or reprogramming by first converting the fibroblast to a pluripotent or totipotent stem cell. Such a pluripotent stem cell is termed an induced pluripotent stem (iPS) cell. An iPS cell that is subsequently converted to a cardiac myocyte (CM) cell is termed an iPS-CM cell. In the examples, iPS-CM derived in vitro from cardiac fibroblasts are used in vivo to select capsid proteins of interest. The disclosure also envisions using the capsid proteins disclosure to in turn generate iPS-CM cells in vitro but, particular, in vivo, as part of a therapeutic gene therapy regimen. Induced cardiomyocyte-like (iCM) cells refer to cells directly reprogrammed into cardiomyocytes.

Induced cardiomyocytes express one or more cardiomyocyte-specific markers, where cardiomyocyte-specific markers include, but are not limited to, cardiac troponin I, cardiac troponin-C, tropomyosin, caveolin-3, myosin heavy chain, myosin light chain-2a, myosin light chain-2v, ryanodine receptor, sarcomeric a-actinin, Nkx2.5, connexin 43, and atrial natriuretic factor. Induced cardiomyocytes can also exhibit sarcomeric structures. Induced cardiomyocytes exhibit increased expression of cardiomyocyte-specific genes ACTC1 (cardiac a-actin), ACTN2 (actinin a2), MYH6 (a-myosin heavy chain), RYR2 (ryanodine receptor 2), MYL2 (myosin regulatory light chain 2, ventricular isoform), MYL7 (myosin regulatory light chain, atrial isoform), TNNT2 (troponin T type 2, cardiac), and NPPA (natriuretic peptide precursor type A), PLN (phospholamban). Expression of fibroblasts markers such as Colla2(collagen la2) is downregulated in induced cardiomyocytes, compared to fibroblasts from which the iCM is derived.

Reprogramming methods involving polypeptide reprogramming factors (in some cases supplemented by small-molecule reprogramming factors supplied in conjuction with the rAAV) include those described in US2018/0112282A1, WO2018/005546, WO2017/173137, US2016/0186141, US2016/0251624, US2014/0301991, and US2013/0216503A1, which are incorporated in their entirety, particularly for the reprogramming methods and factors disclosed.

In some embodiments, cardiac cells are reprogrammed into induced cardiomyocyte-like (iCM) cells using one or more reprogramming factors that modulate the expression of one or more polynucleotides or proteins of interest, such as Achaete-scute homolog 1 (ASCL1), Myocardin (MYOCD), myocyte-specific enhancer factor 2C (MEF2C), and/or T-box transcription factor 5 (TBX5). In some embodiments, the one or more reprogramming factors are provided as a polynucleotide (e.g., an RNA, an mRNA, or a DNA polynucleotide) that encode one or more polynucleotides or proteins of interest. In some embodiments, the one or more reprogramming factors are provided as a protein.

In some embodiments, the reprogramming factors are microRNAs or microRNA antagonists, siRNAs, or small molecules that are capable of increasing the expression of one or more polynucleotides or proteins of interest. In some embodiments, expression of a polynucleotides or proteins of interest is increased by expression of a microRNA or a microRNA antagonist. For example, endogenous expression of an Oct polypeptide can be increased by introduction of microRNA-302 (miR-302), or by increased expression of miR-302. See. e.g., Hu et al., Stem Cells 31(2): 259-68 (2013), which is incorporated herein by reference in its entirety. Hence, miRNA-302 can be an inducer of endogenous Oct polypeptide expression. The miRNA-302 can be introduced alone or with a nucleic acid that encodes the Oct polypeptide. In some embodiments, a suitable nucleic acid gene product is a microRNA. Suitable micrRNAs include, e.g., mir-1, mir-133, mir-208, mir-143, mir-145, and mir-499.

In some embodiments, the methods of the disclosure comprise administering an rAAV virion of the disclosure before, during, or after administration of the small-molecule reprogramming factor. In some embodiments, the small-molecule reprogramming factor is a small molecule selected from the group consisting of SB431542, LDN-193189, dexamethasone, LY364947, D4476, myricetin, IWR1, XAV939, docosahexaenoic acid (DHA), S-Nitroso-TV-acetylpenicillamine (SNAP), Hh-Agl.5, alprostadil, cromakalim, MNITMT, A769662, retinoic acid p-hydoxyanlide, decamethonium dibromide, nifedipine, piroxicam, bacitracin, aztreonam, harmalol hydrochloride, amide-C2 (A7), Ph-C12 (CIO), mCF3-C-7 (J5), G856-7272 (A473), 5475707, or any combination thereof.

In some embodiments, the gene products comprise reprogramming factors that modulate the expression of one or more proteins of interest selected from ASCL1, MYOCD, MEF2C, and TBX5. In some embodiments, the gene products comprise one or more reprogramming factors selected from ASCL1, MYOCD, MEF2C, AND TBX5, CCNB1, CCND1, CDK1, CDK4, AURKB, OCT4, BAF60C, ESRRG, GATA4, GATA6, HAND2, IRX4, ISLL, MESP1, MESP2, NKX2.5, SRF, TBX20, ZFPM2, and miR-133.

In some embodiments, the gene products comprise GATA4, MEF2C, and TBX5 (i.e., GMT). In some embodiments, the gene products comprise MYOCD, MEF2C, and TBX5 (i.e., MyMT). In some embodiments, the gene products comprise MYOCD, ASCL1, MEF2C, and TBX5 (i.e., MyAMT). In some embodiments, the gene products comprise MYOCD and ASCL1 (i.e., MyA). In some embodiments, the gene products comprise GATA4, MEF2C, TBX5, and MYOCD (i.e., 4F). In other embodiments, the gene products comprise GATA4, MEF2C, TBX5, ESSRG, MYOCD, ZFPM2, and MESP1 (i.e., 7F). In some embodiments, the gene products comprise one or more of ASCL1, MEF2C, GATA4, TBX5, MYOCD, ESRRG, AND MESPL.

In some embodiments, the rAAV virions generate cardiac myocytes in vitro or in vivo. Cardiomyocytes or cardiac myocytes are the muscle cells that make up the cardiac muscle. Each myocardial cell contains myofibrils, which are long chains of sarcomeres, the contractile units of muscle cells. Cardiomyocytes show striations similar to those on skeletal muscle cells, but unlike multinucleated skeletal cells, they contain only one nucleus. Cardiomyocytes have a high mitochondrial density, which allows them to produce ATP quickly, making them highly resistant to fatigue. Mature cardiomyocytes can express one or more of the following cardiac markers: α-Actinin, MLC2v, MY20, cMHC, NKX2-5, GATA4, cTNT, cTNI, MEF2C, MLC2a, or any combination thereof. In some embodiments, the mature cardiomyocytes express NKX2-5, MEF2C or a combination thereof. In some embodiments, cardiac progenitor cells express early stage cardiac progenitor markers such as GATA4, ISL1 or a combination thereof.

In some embodiments, the gene product is a polynucleotide. In some embodiments, as described below, the gene product is a guide RNA capable of binding to an RNA-guided endonuclease. In some embodiments, the gene product is an inhibitory nucleic acid capable of reducing the level of an mRNA and/or a polypeptide gene product, e.g., in a cardiac cell. For example, in some embodiments, the polynucleotide gene product is an interfering RNA capable of selectively inactivating a transcript encoded by an allele that causes a cardiac disease or disorder. As an example, the allele is a myosin heavy chain 7, cardiac muscle, beta (MYH7) allele that comprises a hypertrophic cardiomyopathy-causing mutation. Other examples include, e.g., interfering RNAs that selectively inactivate a transcript encoded by an allele that causes hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM) or Left Ventricular Non-Compaction (LVNC), where the allele is a MYL3 (myosin light chain 3, alkali, ventricular, skeletal slow), MYH7, TNNI3 (troponin I type 3 (cardiac)), TNNT2 (troponin T type 2 (cardiac)), TPM1 (tropomyosin 1 (alpha)) or ACTC1 allele comprising an HCM-causing, a DCM-causing or a LVNC-causing mutation. See. e.g., U.S. Pat. Pub. No. 2016/0237430 for examples of cardiac disease-causing mutations.

In some embodiments, the gene product is a polypeptide-encoding RNA. In some embodiments, the gene product is an interfering RNA. In some embodiments, the gene product is an aptamer. In some embodiments, the gene product is a polypeptide. In some embodiments, the gene product is a therapeutic polypeptide, e.g., a polypeptide that provides clinical benefit. In some embodiments, the gene product is a site-specific nuclease that provide for site-specific knock-down of gene function. In some embodiments, the gene product is an RNA-guided endonuclease that provides for modification of a target nucleic acid. In some embodiments, the gene products are: i) an RNA-guided endonuclease that provides for modification of a target nucleic acid; and ii) a guide RNA that comprises a first segment that binds to a target sequence in a target nucleic acid and a second segment that binds to the RNA-guided endonuclease. In some embodiments, the gene products are: i) an RNA-guided endonuclease that provides for modification of a target nucleic acid; ii) a first guide RNA that comprises a first segment that binds to a first target sequence in a target nucleic acid and a second segment that binds to the RNA-guided endonuclease; and iii) a first guide RNA that comprises a first segment that binds to a second target sequence in the target nucleic acid and a second segment that binds to the RNA-guided endonuclease.

A nucleotide sequence encoding a heterologous gene product in an rAAV virion of the present disclosure can be operably linked to a promoter. For example, a nucleotide sequence encoding a heterologous gene product in an rAAV virion of the present disclosure can be operably linked to a constitutive promoter, a regulatable promoter, or a cardiac cell-specific promoter. Suitable constitutive promoters include a human elongation factor 1 α subunit (EF1α) promoter, a β-actin promoter, an α-actin promoter, a β-glucuronidase promoter, CAG promoter, super core promoter, and a ubiquitin promoter. In some embodiments, a nucleotide sequence encoding a heterologous gene product in an rAAV virion of the present disclosure is operably linked to a cardiac-specific transcriptional regulator element (TRE), where cardiac-specific TREs include promoters and enhancers. Suitable cardiac-specific TREs include, but are not limited to, TREs derived from the following genes: myosin light chain-2 (MLC-2), a-myosin heavy chain (a-MHC), desmin, AE3, cardiac troponin C (cTnC, and cardiac actin. Franz et al. (1997) Cardiovasc. Res. 35:560-566; Robbins et al. (1995) Ann. NY. Acad. Sci. 752:492-505; Linn et al. (1995) Circ. Res. 76:584-591; Parmacek et al. (1994)Mol. Cell. Biol. 14: 1870-1885; Hunter et al. (1993) Hypertension 22:608-617; and Sartorelli et al. (1992)Proc. Natl. Acad. Sci. USA 89:4047-4051. See also, Pacak et al. (2008) Genet Vaccines Ther. 6:13. In some embodiments, the promoter is an α-MHC promoter, an MLC-2 promoter, or cTnT promoter.

The polynucleotide encoding a gene product is operably linked to a promoter and/or enhancer to facilitate expression of the gene product. Depending on the host/vector system utilized, any of a number of suitable transcription and translation control elements, including constitutive and inducible promoters, transcription enhancer elements, transcription terminators, etc. may be used in the rAAV virion (e.g., Bitter et al. (1987) Methods in Enzymology, 153:516-544).

Separate promoters and/or enhancers can be employed for each of the polynucleotides. In some embodiments, the same promoter and/or enhance is used for two or more polynucleotides in a single open reading frame. Vectors employing this configuration of genetic elements are termed “polycistronic.” An illustrative example of a polycistronic vector comprises an enhancer and a promoter operatively linked to a single open-reading frame comprising two or more polynucleotides linked by 2A region(s), whereby expression of the open-reading frame result in multiple polypeptides being generated co-translationally. The 2A region is believed to mediate generation of multiple polypeptide sequences through codon skipping; however, the present disclosure relates also to polycistronic vectors that employ post-translational cleavage to generate two or more proteins of interest from the same polynucleotide. Illustrative 2A sequences, vectors, and associated methods are provided in US20040265955A1, which is incorporated herein by reference.

Non-limiting examples of suitable eukaryotic promoters (promoters functional in a eukaryotic cell) include CMV, CMV immediate early, HSV thymidine kinase, early and late SV40, long terminal repeats (LTRs) from retrovirus, and mouse metallothionein-I. In some embodiments, promoters that are capable of conferring cardiac specific expression will be used. Non-limiting examples of suitable cardiac specific promoters include desmin (Des), alpha-myosin heavy chain (a-MHC), myosin light chain 2 (MLC-2), cardiac troponin T (cTnT) and cardiac troponin C (cTnC). Non-limiting examples of suitable neuron specific promoters include synapsin I (SYN), calcium/calmodulin-dependent protein kinase II, tubulin alpha I, neuron-specific enolase and platelet-derived growth factor beta chain promoters and hybrid promoters by fusing cytomegalovirus enhancer (E) to those neuron-specific promoters.

Examples of suitable promoters for driving expression reprogramming factors include, but are not limited to, retroviral long terminal repeat (LTR) elements; constitutive promoters such as CMV, HSV1-TK, SV40, EF-1a, β-actin, phosphoglycerol kinase (PGK); inducible promoters, such as those containing Tet-operator elements; cardiac specific promoters, such as desmin (DES), alpha-myosin heavy chain (a-MHC), myosin light chain 2 (MLC-2), cardiac troponin T (cTnT) and cardiac troponin C (cTnC); neural specific promoters, such as nestin, neuronal nuclei (NeuN), microtubule-associate protein 2 (MAP2), beta III tubulin, neuron specific enolase (NSE), oligodendrocyte lineage (Oligl/2), and glial fibrillary acidic protein (GFAP); and pancreatic specific promoters, such as Pax4, Nkx2.2, Ngn3, insulin, glucagon, and somatostatin.

In some embodiments, a polynucleotide is operably linked to a cell type-specific transcriptional regulator element (TRE), where TREs include promoters and enhancers. Suitable TREs include, but are not limited to, TREs derived from the following genes: myosin light chain-2, a-myosin heavy chain, AE3, cardiac troponin C, and cardiac actin. Franz et al. (1997) Cardiovasc. Res. 35:560-566; Robbins et al. (1995) Ann. N. Y. Acad. Sci. 752:492-505; Linn et al. (1995) Circ. Res. 76:584-591; Parmacek et al. (1994) Cell. Biol. 14:1870-1885; Hunter et al. (1993) Hypertension 22:608-617; and Sartorelli et al. (1992) PNAS USA 89:4047-4051.

The promoter can be one naturally associated with a gene or nucleic acid segment. Similarly, for RNAs (e.g., microRNAs), the promoter can be one naturally associated with a microRNA gene (e.g., an miRNA-302 gene). Such a naturally associated promoter can be referred to as the “natural promoter” and may be obtained by isolating the 5′ non-coding sequences located upstream of the coding segment and/or exon. Similarly, an enhancer may be one naturally associated with a nucleic acid sequence. However, the enhancer can be located either downstream or upstream of that sequence.

Alternatively, certain advantages will be gained by positioning the coding nucleic acid segment under the control of a recombinant or heterologous promoter, which refers to a promoter that is not normally associated with a nucleic acid in its natural environment. A recombinant or heterologous enhancer refers also to an enhancer not normally associated with a nucleic acid sequence in its natural environment. Such promoters or enhancers can include promoters or enhancers of other genes, and promoters or enhancers isolated from any other prokaryotic, viral, or eukaryotic cell, and promoters or enhancers not “naturally occurring,” i.e., containing different elements of different transcriptional regulatory regions, and/or mutations that alter expression. In addition to producing nucleic acid sequences of promoters and enhancers synthetically, sequences may be produced using recombinant cloning and/or nucleic acid amplification technology, including PCR™, in connection with the compositions disclosed herein (see U.S. Pat. Nos. 4,683,202, 5,928,906, each incorporated herein by reference).

The promoters employed may be constitutive, inducible, developmentally-specific, tissue-specific, and/or useful under the appropriate conditions to direct high level expression of the nucleic acid segment. For example, the promoter can be a constitutive promoter such as, a CMV promoter, a CMV cytomegalovirus immediate early promoter, a CAG promoter, an EF-1α promoter, a HSV1-TK promoter, an SV40 promoter, a β-actin promoter, a PGK promoter, or a combination thereof. Examples of eukaryotic promoters that can be used include, but are not limited to, constitutive promoters, e.g., viral promoters such as CMV, SV40 and RSV promoters, as well as regulatable promoters, e.g., an inducible or repressible promoter such as the tet promoter, the hsp70 promoter and a synthetic promoter regulated by CRE. In certain embodiments, cell type-specific promoters are used to drive expression of reprogramming factors in specific cell types. Examples of suitable cell type-specific promoters useful for the methods described herein include, but are not limited to, the synthetic macrophage-specific promoter described in He et al (2006), Human Gene Therapy 17:949-959; the granulocyte and macrophage-specific lysozyme M promoter (see, e.g., Faust et al (2000), Blood 96(2):719-726); and the myeloid-specific CD11b promoter (see, e.g., Dziennis et al (1995), Blood 85(2):319-329). Other examples of promoters that can be employed include a human EF1α elongation factor promoter, a CMV cytomegalovirus immediate early promoter, a CAG chicken albumin promoter, a viral promoter associated with any of the viral vectors described herein, or a promoter that is homologous to any of the promoters described herein (e.g., from another species). Examples of prokaryotic promoters that can be used include, but are not limited to, SP6, T7, T5, tac, bla, trp, gal, lac, or maltose promoters.

In some embodiments, an internal ribosome entry sites (IRES) element can be used to create multigene, or polycistronic, messages. IRES elements are able to bypass the ribosome scanning model of 5′-methylated Cap dependent translation and begin translation at internal sites (Pelletier and Sonenberg, Nature 334(6180):320-325 (1988)). IRES elements from two members of the picomavirus family (polio and encephalomyocarditis) have been described (Pelletier and Sonenberg, Nature 334(6180):320-325 (1988)), as well an IRES from a mammalian message (Macejak & Samow, Nature 353:90-94 (1991)). IRES elements can be linked to heterologous open reading frames. Multiple open reading frames can be transcribed together, each separated by an IRES, creating polycistronic messages. By virtue of the IRES element, each open reading frame is accessible to ribosomes for efficient translation. Multiple genes can be efficiently expressed using a single promoter/enhancer to transcribe a single message (see U.S. Pat. Nos. 5,925,565 and 5,935,819, herein incorporated by reference).

In some embodiments, a nucleotide sequence is operably linked to a polyadenylation sequence. Suitable polyadenylation sequences include bovine growth hormone polyA signal (bGHpolyA) and short poly A signal. Optionally the rAAV vectors of the disclosure comprise the Woodchuck Post-transcriptional Regulatory Element (WPRE). In some embodiments, the polynucleotide encoding gene products are join by sequences include so-called self-cleaving peptide, e.g. P2A peptides.

In some embodiments, the gene product comprises a site-specific endonuclease that provides for site-specific knock-down of gene function, e.g., where the endonuclease knocks out an allele associated with a cardiac disease or disorder. For example, where a dominant allele encodes a defective copy of a gene that, when wild-type, is a cardiac structural protein and/or provides for normal cardiac function, a site-specific endonuclease can be targeted to the defective allele and knock out the defective allele. In some embodiments, a site-specific endonuclease is an RNA-guided endonuclease.

In addition to knocking out a defective allele, a site-specific nuclease can also be used to stimulate homologous recombination with a donor DNA that encodes a functional copy of the protein encoded by the defective allele. For example, a subject rAAV virion can be used to deliver both a site-specific endonuclease that knocks out a defective allele a functional copy of the defective allele (or fragment thereof), resulting in repair of the defective allele, thereby providing for production of a functional cardiac protein (e.g., functional troponin, etc.). In some embodiments, a subject rAAV virion comprises a heterologous nucleotide sequence that encodes a site-specific endonuclease and a heterologous nucleotide sequence that encodes a functional copy of a defective allele, where the functional copy encodes a functional cardiac protein. Functional cardiac proteins include, e.g., troponin, a chloride ion channel, and the like.

Site-specific endonucleases that are suitable for use include, e.g., zinc finger nucleases (ZFNs); meganucleases; and transcription activator-like effector nucleases (TALENs), where such site-specific endonucleases are non-naturally occurring and are modified to target a specific gene. Such site-specific nucleases can be engineered to cut specific locations within a genome, and non-homologous end joining can then repair the break while inserting or deleting several nucleotides. Such site-specific endonucleases (also referred to as “INDELs”) then throw the protein out of frame and effectively knock out the gene. See. e.g., U.S. Pat. Pub. No. 2011/0301073. Suitable site-specific endonucleases include engineered meganuclease re-engineered homing endonucleases. Suitable endonucleases include an I-Tevl nuclease. Suitable meganucleases include I-Scel (see, e.g., Bellaiche et al. (1999) Genetics 152: 1037); and I-Crel (see, e.g., Heath et al. (1997) Nature Sructural Biology 4:468). Site-specific endonucleases that are suitable for use include CRISPRi systems and the Cas9-based SAM system.

In some embodiments, the gene product is an RNA-guided endonuclease. In some embodiments, the gene product comprises an RNA comprising a nucleotide sequence encoding an RNA-guided endonuclease. In some embodiments, the gene product is a guide RNA, e.g., a single-guide RNA. In some embodiments, the gene products are: 1) a guide RNA; and 2) an RNA-guided endonuclease. The guide RNA can comprise: a) a protein-binding region that binds to the RNA-guided endonuclease; and b) a region that binds to a target nucleic acid. An RNA-guided endonuclease is also referred to herein as a “genome editing nuclease.”

Examples of suitable genome editing nucleases are CRISPR/Cas endonucleases (e.g., class 2 CRISPR/Cas endonucleases such as a type II, type V, or type VI CRISPR/Cas endonucleases). A suitable genome editing nuclease is a CRISPR/Cas endonuclease (e.g., a class 2 CRISPR/Cas endonuclease such as a type II, type V, or type VI CRISPR/Cas endonuclease). In some embodiments, the gene product comprises a class 2 CRISPR/Cas endonuclease. In some embodiments, the gene product comprises a class 2 type II CRISPR/Cas endonuclease (e.g., a Cas9 protein). In some embodiments, the gene product comprises a class 2 type V CRISPR/Cas endonuclease (e.g., a Cpfl protein, a C2c1 protein, or a C2c3 protein). In some embodiments, the gene product comprises a class 2 type VI CRISPR/Cas endonuclease (e.g., a C2c2 protein; also referred to as a “Casl3a” protein). In some embodiments, the gene product comprises a CasX protein. In some embodiments, the gene product comprises a CasY protein.

Methods of Use

In some embodiments, the disclosure provides methods of identifying AAV capsid proteins that confer on rAAV virions increased transduction efficiency in target cells. The methods comprise providing a population of rAAV virions whose rAAV genomes comprise a library of cap polynucleotides encoding variant AAV capsid proteins; optionally contacting the population with non-target cells for a time sufficient to permit attachment of undesired rAAV virions to the non-target cells; contacting the population with target cells for a time sufficient to permit transduction of the cap polynucleotide into the target cells by the rAAV virions; and sequencing the cap polynucleotides from the target cells, thereby identifying AAV capsid proteins that confer increased transduction efficiency in the target cells. In some embodiments, the method further comprises depleting the population of rAAV virions by contacting the population with non-target cells for time sufficient to permit attachment of the rAAV virions to the non-target cells. Non-limiting examples of such identifications methods are provided in the Examples.

The disclosure provides methods for generating cardiomyocytes and/or cardiomyocyte-like cells in vitro using an rAAV virion. Selected starting cells are transduced with an rAAV and optionally exposed to small-molecule reprogramming factors (before, during, or after transduction) for a time and under conditions sufficient to convert the starting cells across lineage and/or differentiation boundaries to form cardiac progenitor cells and/or cardiomyocytes. In some embodiments, the starting cells are fibroblast cells. In some embodiments, the starting cells express one or more markers indicative of a differentiated phenotype. The time for conversion of starting cells into cardiac progenitor and cardiomyocyte cells can vary. For example, the starting cells can be incubated after treatment with one or more polynucleotides or proteins of interest until cardiac or cardiomyocyte cell markers are expressed. Such cardiac or cardiomyocyte cell markers can include any of the following markers: α-GATA4, TNNT2, MYH6, RYR2, NKX2-5, MEF2C, ANP, Actinin, MLC2v, MY20, cMHC, ISL1, cTNT, cTNI, and MLC2a, or any combination thereof. In some embodiments, the induced cardiomycocyte cells are negative for one or more neuronal cells markers. Such neuronal cell markers can include any of the following markers: DCX, TUBB3, MAP2, and ENO2.

Incubation can proceed until cardiac progenitor markers are expressed by the starting cells. Such cardiac progenitor markers include GATA4, TNNT2, MYH6, RYR2, or a combination thereof. The cardiac progenitor markers such as GATA4, TNNT2, MYH6, RYR2, or a combination thereof can be expressed by about 8 days, or by about 9 days, or by about 10 days, or by about 11 days, or by about 12 days, or by about 14 days, or by about 15 days, or by about 16 days, or by about 17 days, or by about 18 days, or by about 19 days, or by about 20 days after starting incubation of cells in the compositions described herein. Further incubation of the cells can be performed until expression of late stage cardiac progenitor markers such as NKX2-5, MEF2C or a combination thereof occurs.

Reprogramming efficiency may be measured as a function of cardiomyocyte markers. Such pluripotency markers include, but are not limited to, the expression of cardiomyocyte marker proteins and mRNA, cardiomyocyte morphology and electrophysiological phenotype. Non-limiting examples of cardiomyocyte markers include, a-sarcoglycan, atrial natriuretic peptide (ANP), bone morphogenetic protein 4 (BMP4), connexin 37, connexin 40, crypto, desmin, GATA4, GATA6, MEF2C, MYH6, myosin heavy chain, NKX2.5, TBX5, and Troponin T.

The expression of various markers specific to cardiomyocytes may be detected by conventional biochemical or immunochemical methods (e.g., enzyme-linked immunosorbent assay, immunohistochemical assay, and the like). Alternatively, expression of a nucleic acid encoding a cardiomyocyte-specific marker can be assessed. Expression of cardiomyocyte-specific marker-encoding nucleic acids in a cell can be confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) or hybridization analysis, molecular biological methods which have been commonly used in the past for amplifying, detecting and analyzing mRNA coding for any marker proteins. Nucleic acid sequences coding for markers specific to cardiomyocytes are known and are available through public databases such as GenBank. Thus, marker-specific sequences needed for use as primers or probes are easily determined.

Cardiomyocytes exhibit some cardiac-specific electrophysiological properties. One electrical characteristic is an action potential, which is a short-lasting event in which the difference of potential between the interior and the exterior of each cardiac cell rises and falls following a consistent trajectory. Another electrophysiological characteristic of cardiomyocytes is the cyclic variations in the cytosolic-free Ca²⁺ concentration, named as Ca²⁺ transients, which are employed in the regulation of the contraction and relaxation of cardiomyocytes. These characteristics can be detected and evaluated to assess whether a population of cells has been reprogrammed into cardiomyocytes.

The present disclosure provides a method of delivering a gene product to a cardiac cell, e.g., a cardiac fibroblast. The methods generally involve infecting a cardiac cell (e.g., a cardiac fibroblast) with an rAAV virion, where the gene product(s) encoded by the heterologous nucleic acid present in the rAAV virion is/are produced in the cardiac cell (e.g., cardiac fibroblast). Delivery of gene product(s) to a cardiac cell (e.g., cardiac fibroblast) can provide for treatment of a cardiac disease or disorder. Delivery of gene product(s) to a cardiac cell (e.g., cardiac fibroblast) can provide for generation of an induced cardiomyocyte-like (iCM) cell from the cardiac fibroblast. Delivery of gene product(s) to a cardiac cell (e.g., cardiac fibroblast) can provide for editing of the genome of the cardiac cell (e.g., cardiac fibroblast).

In some embodiments, infecting or transducing a cardiac cell (e.g., cardiac fibroblast) is carried out in vitro. In some embodiments, infecting or transducing a cardiac cell (e.g., cardiac fibroblast) is carried out in vitro; and the infected/transduced cardiac cell (e.g., cardiac fibroblast) is introduced into (e.g., transfused into or implanted into) an individual in need thereof, e.g., directly into cardiac tissue of an individual in need thereof. For in vitro transduction, an effective amount of rAAV virions to be delivered to cells is from about 10⁵ to about 10¹³ of the rAAV virions. Other effective dosages can be readily established by one of ordinary skill in the art through routine trials establishing dose response curves.

In some embodiments, infecting a cardiac cell (e.g., cardiac fibroblast) is carried out in vivo. For example, in some embodiments, an effective amount of an rAAV virion of the present disclosure is administered directly into cardiac tissue of an individual in need thereof. An “effective amount” will fall in a relatively broad range that can be determined through experimentation and/or clinical trials. For example, for in vivo injection, i.e., injection directly into cardiac tissue, a therapeutically effective dose will be on the order of from about 10⁶ to about 10⁵ of the rAAV virions, e.g., from about 10⁵ to 10¹² rAAV virions, of the present disclosure. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via intramyocardial injection through the epicardium. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via vascular delivery through the coronary artery. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through the superior vena cava. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through a peripheral vein.

For example, from about 10⁴ to about 10⁵, from about 10⁵ to about 10⁶, from about 10⁶ to about 10⁷, from about 10⁶ to about 10⁷, from about 10⁷ to about 10⁸, from about 10⁸ to about 10⁹, from about 10⁹ to about 10¹⁰, from about 10¹⁰ to about 10¹¹, to about 10¹¹, from about 10¹¹ to about 10¹², from about 10¹² to about 10¹³, from about 10¹³ to about 10¹⁴, from about 10¹⁴ to about 10¹⁵ genome copies, or more than 10¹⁵ genome copies, of an rAAV virion of the present disclosure are administered to an individual, e.g., are administered directly into cardiac tissue in the individual, or are administered via another route. The number of rAAV virions administered to an individual can be expressed in viral genomes (vg) per kilogram (kg) body weight of the individual. In some embodiments, and effective amount of an rAAV virion of the present disclosure is from about 10² vg/kg to 10⁴ vg/kg, from about 10⁴ vg/kg to about 10⁶ vg/kg, from about 10⁶ vg/kg to about 10⁸ vg/kg, from about 10⁸ vg/kg to about 10¹⁰ vg/kg, from about 10¹⁰ vg/kg to about 10¹² vg/kg, from about 10¹² vg/kg to about 10¹⁴ vg/kg, from about 10¹⁴ vg/kg to about 10¹⁶ vg/kg, from about 10¹⁶ vg/kg to about 10¹⁸ vg/kg, or more than 10¹⁸ vg/kg.

In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via intramyocardial injection through the epicardium. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via vascular delivery through the coronary artery. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through the superior vena cava. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through a peripheral vein.

In some embodiments, more than one administration (e.g., two, three, four or more administrations) may be employed to achieve the desired level of gene expression. In some embodiments, the more than one administration is administered at various intervals, e.g., daily, weekly, twice monthly, monthly, every 3 months, every 6 months, yearly, etc. In some embodiments, multiple administrations are administered over a period of time of from 1 month to 2 months, from 2 months to 4 months, from 4 months to 8 months, from 8 months to 12 months, from 1 year to 2 years, from 2 years to 5 years, or more than 5 years.

The present disclosure provides a method of reprogramming a cardiac fibroblast to generate an induced cardiomyocyte-like cell (iCM). The method generally involves infecting a cardiac fibroblast with an rAAV virion of the present disclosure, where the rAAV virion comprises a heterologous nucleic acid comprising a nucleotide sequence encoding one or more reprogramming factors.

The expression of various markers specific to cardiomyocytes is detected by conventional biochemical or immunochemical methods (e.g., enzyme-linked immunosorbent assay; immunohistochemical assay; and the like). Alternatively, expression of nucleic acid encoding a cardiomyocyte-specific marker can be assessed. Expression of cardiomyocyte-specific marker-encoding nucleic acids in a cell can be confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) or hybridization analysis, molecular biological methods which have been commonly used in the past for amplifying, detecting and analyzing mRNA coding for any marker proteins. Nucleic acid sequences coding for markers specific to cardiomyocytes are known and are available through public data bases such as GenBank; thus, marker-specific sequences needed for use as primers or probes is easily determined.

Induced cardiomyocytes can also exhibit spontaneous contraction. Whether an induced cardiomyocyte exhibits spontaneous contraction can be determined using standard electrophysiological methods (e.g., patch clamp).

In some embodiments, induced cardiomyocytes can exhibit spontaneous Ca²⁺ oscillations. Ca²⁺ oscillations can be detected using standard methods, e.g., using any of a variety of calcium-sensitive dyes, intracellular Ca²⁺ ion-detecting dyes include, but are not limited to, fura-2, bis-fura 2, indo-1, Quin-2, Quin-2 AM, Benzothiaza-1, Benzothiaza-2, indo-5F, Fura-FF, BTC, Mag-Fura-2, Mag-Fura-5, Mag-Indo-1, fluo-3, rhod-2, rhod-3, fura-4F, fura-5F, fura-6F, fluo-4, fluo-5F, fluo-5N, Oregon Green 488 BAPTA, Calcium Green, Calcein, Fura-C18, Calcium Green-C18, Calcium Orange, Calcium Crimson, Calcium Green-5N, Magnesium Green, Oregon Green 488 BAPTA-1, Oregon Green 488 BAPTA-2, X-rhod-1, Fura Red, Rhod-5F, Rhod-5N, X-Rhod-5N, Mag-Rhod-2, Mag-X-Rhod-1, Fluo-5N, Fluo-5F, Fluo-4FF, Mag-Fluo-4, Aequorin, dextran conjugates or any other derivatives of any of these dyes, and others (see, e.g., the catalog or Internet site for Molecular Probes, Eugene, see, also, Nuccitelli, ed., Methods in Cell Biology, Volume 40: A Practical Guide to the Study of Calcium in Living Cells, Academic Press (1994); Lambert, ed., Calcium Signaling Protocols (Methods in Molecular Biology Volume 114), Humana Press (1999); W. T. Mason, ed., Fluorescent and Luminescent Probes for Biological Activity. A Practical Guide to Technology for Quantitative Real-Time Analysis, Second Ed, Academic Press (1999); Calcium Signaling Protocols (Methods in Molecular Biology), 2005, D. G. Lamber, ed., Humana Press.).

In some embodiments, an iCM is generated in vitro; and the iCM is introduced into an individual, e.g., the iCM is implanted into a cardiac tissue of an individual in need thereof. A method of the present disclosure can comprise infecting a population of cardiac fibroblasts in vitro, to generate a population of iCMs; and the population of iCMs is implanted into a cardiac tissue of an individual in need thereof.

In some embodiments, an iCM is generated in vivo. For example, in some embodiments, an rAAV virion of the present disclosure that comprises a heterologous nucleic acid comprising a nucleotide sequence encoding one or more reprogramming factors is administered to an individual. In some embodiments, the rAAV virion is administered directly into cardiac tissue of an individual in need thereof. In some embodiments, from about 10⁶ to about 10⁵, from about 10⁵ to about 10⁹, from about 10⁹ to about 10¹⁰, from about 10¹⁰ to about 10¹¹, from about 10¹¹ to about 10¹², from about 10¹² to about 10¹³, from about 10¹³ to about 10¹⁴, from about 10¹⁴ to about 10¹⁵ genome copies, or more than 10¹⁵ genome copies, of an rAAV virion of the present disclosure that comprises a heterologous nucleic acid comprising a nucleotide sequence encoding one or more reprogramming factors are administered to an individual, e.g., are administered directly into cardiac tissue in the individual or via another route of administration. The number of rAAV virions administered to an individual can be expressed in viral genomes (vg) per kilogram (kg) body weight of the individual. In some embodiments, and effective amount of an rAAV virion of the present disclosure is from about 10² vg/kg to 10⁴ vg/kg, from about 10⁴ vg/kg to about 10⁶ vg/kg, from about 10⁶ vg/kg to about 10⁸ vg/kg, from about 10⁸ vg/kg to about 10¹⁰ vg/kg, from about 10¹⁰ vg/kg to about 10¹² vg/kg, from about 10¹² vg/kg to about 10¹⁴ vg/kg, from about 10¹⁴ vg/kg to about 10¹⁴ vg/kg, from about 10¹⁴ vg/kg to about 10¹⁶ vg/kg, or more than 10¹⁶ vg/kg. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via intramyocardial injection through the epicardium. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via vascular delivery through the coronary artery. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through the superior vena cava. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through a peripheral vein.

The present disclosure provides a method of modifying (“editing”) the genome of a cardiac cell. The present disclosure provides a method of modifying (“editing”) the genome of a cardiac fibroblast. The present disclosure provides a method of modifying (“editing”) the genome of a cardiomyocyte. The methods generally involve infecting a cardiac cell (e.g., a cardiac fibroblast or a cardiomyocyte) with an rAAV virion of the present disclosure, where the rAAV virion comprises a heterologous nucleic acid comprising a nucleotide sequence encoding a genome-editing endonuclease. In some embodiments, the method comprises infecting a cardiac fibroblast or a cardiomyocyte with an rAAV virion of the present disclosure, where the rAAV virion comprises a heterologous nucleic acid comprising a nucleotide sequence encoding an RNA-guided genome-editing endonuclease. In some embodiments, the method comprises infecting a cardiac fibroblast or a cardiomyocyte with an rAAV virion of the present disclosure, where the rAAV virion comprises a heterologous nucleic acid comprising a nucleotide sequence encoding: i) an RNA-guided genome-editing endonuclease; and ii) one or more guide RNAs.

In some embodiments, the method comprises infecting a cardiac fibroblast or a cardiomyocyte with an rAAV virion of the present disclosure, where the rAAV virion comprises a heterologous nucleic acid comprising a nucleotide sequence encoding: i) an RNA-guided genome-editing endonuclease; ii) a guide RNAs; and iii) a donor template DNA. Suitable RNA-guided genome-editing endonucleases are described above.

In some embodiments, infecting a cardiac cell (e.g., cardiac fibroblast; a cardiomyocyte) is carried out in vitro. In some embodiments, infecting a cardiac cell (e.g., cardiac fibroblast; a cardiomyocyte) is carried out in vitro; and the infected cardiac cell (e.g., cardiac fibroblast) is introduced into (e.g., implanted into) an individual in need thereof, e.g., directly into cardiac tissue of an individual in need thereof. For in vitro transduction, an effective amount of rAAV virions to be delivered to cells will be on the order of from about 10^(s), to about 10¹³ of the rAAV virions. Other effective dosages can be readily established by one of ordinary skill in the art through routine trials establishing dose response curves.

In some embodiments, infecting a cardiac cell (e.g., cardiac fibroblast; a cardiomyocyte) is carried out in vivo. For example, in some embodiments, an effective amount of an rAAV virion of the present disclosure is administered directly into cardiac tissue of an individual in need thereof. An “effective amount” will fall in a relatively broad range that can be determined through experimentation and/or clinical trials. For example, for in vivo injection, i.e., injection directly into cardiac tissue, a therapeutically effective dose will be on the order of from about 10⁶ to about 10¹⁵ of the rAAV virions, e.g., from about 10¹¹ to 10¹² rAAV virions, of the present disclosure. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via intramyocardial injection through the epicardium. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via vascular delivery through the coronary artery. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through the superior vena cava. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through a peripheral vein.

For example, from about 10⁶ to about 10⁷, from about 10⁷ to about 10⁸, from about 10⁸ to about 10⁹, from about 10⁹ to about 10¹⁰, from about 10¹⁰ to about 10¹¹, from about 10¹¹ to about 10¹², from about 10¹² to about 10¹³, from about 10¹³ to about 10¹⁴, from about 10¹⁴ to about 10¹⁵ genome copies, or more than 10¹⁵ genome copies, of an rAAV virion of the present disclosure are administered to an individual, e.g., are administered directly into cardiac tissue in the individual. The number of rAAV virions administered to an individual can be expressed in viral genomes (vg) per kilogram (kg) body weight of the individual. In some embodiments, and effective amount of an rAAV virion of the present disclosure is from about 10² vg/kg to 10⁴ vg/kg, from about 10⁴ vg/kg to about 10⁶ vg/kg, from about 10⁶ vg/kg to about 10⁸ vg/kg, from about 10⁸ vg/kg to about 10¹⁰ vg/kg, from about 10¹⁰ vg/kg to about 10¹² vg/kg, from about 10¹² vg/kg to about 10¹⁴ vg/kg, from about 10¹⁴ vg/kg to about 10¹⁶ vg/kg, from about 10¹⁶ vg/kg to about 10¹⁸ vg/kg, or more than 10¹⁸ vg/kg. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via intramyocardial injection through the epicardium. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via vascular delivery through the coronary artery. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through the superior vena cava. In some embodiments, an effective amount of an rAAV virion of the present disclosure is administered via systemic delivery through a peripheral vein.

In some embodiments, the genome editing comprises homology-directed repair (HDR). In some embodiments, the HDR corrects a defect in an endogenous target nucleic acid in the cardiac fibroblast or the cardiomyocyte, where the defect is associated with, or leads to, a defect in structure and/or function of the cardiac fibroblast or the cardiomyocyte, or a component of the cardiac fibroblast or the cardiomyocyte.

In some embodiments, the genome editing comprises non-homologous end joining (NHEJ). In some embodiments, the NHEJ deletes a defect in an endogenous target nucleic acid in the cardiac fibroblast or the cardiomyocyte, where the defect is associated with, or leads to, a defect in structure and/or function of the cardiac fibroblast or the cardiomyocyte, or a component of the cardiac fibroblast or the cardiomyocyte.

A method of the present disclosure for editing the genome of a cardiac cell can be used to correct any of a variety of genetic defects that give rise to a cardiac disease or disorder. Mutations of interest include mutations in one or more of the following genes: cardiac troponin T (TNNT2); myosin heavy chain (MYH7); tropomyosin 1 (TPM1); myosin binding protein C (MYBPC3); 5′-AMP-activated protein kinase subunit gamma-2 (PRKAG2); troponin I type 3 (TNNI3); titin (TTN); myosin, light chain 2 (MYL2); actin, alpha cardiac muscle 1 (ACTC1); potassium voltage-gated channel, KQT-like subfamily, member 1 (KCNQ1); plakophilin 2 (PKP2); myocyte enhancer factor 2c (MEF2C); and cardiac LIM protein (CSRP3). Specific mutations of interest include, without limitation, MYH7 R663H mutation; TNNT2 R173W; PKP2 2013delC mutation; PKP2 Q617X mutation; and KCNQ1 G269S missense mutation. Mutations of interest include mutations in one or more of the following genes: MYH6, ACTN2, SERCA2, GATA4, TBX5, MYOCD, NKX2-5, NOTCH1, MEF2C, HAND2, and HAND1. In some embodiments, the mutations of interest include mutations in the following genes: MEF2C, TBX5, and MYOCD. Cardiac diseases and disorders that can be treated with a method of the present disclosure include coronary heart disease, cardiomyopathy, endocarditis, congenital cardiovascular defects, and congestive heart failure. Cardiac diseases and disorders that can be treated with a method of the present disclosure include hypertrophic cardiomyopathy; a valvular heart disease; myocardial infarction; congestive heart failure; long QT syndrome; atrial arrhythmia; ventricular arrhythmia; diastolic heart failure; systolic heart failure; cardiac valve disease; cardiac valve calcification; left ventricular non-compaction; ventricular septal defect; and ischemia.

Methods of Treatment

The disclosure provides a methods of treating a cardiac pathology in a subject in need thereof, comprising administering a therapeutically effective amount of a pharmaceutical composition comprising an rAAV virion to the subject, wherein the rAAV virion transduces cardiac tissue.

Subjects in need of treatment using compositions and methods of the present disclosure include, but are not limited to, individuals having a congenital heart defect, individuals suffering from a degenerative muscle disease, individuals suffering from a condition that results in ischemic heart tissue (e.g., individuals with coronary artery disease), and the like. In some examples, a method is useful to treat a degenerative muscle disease or condition (e.g., familial cardiomyopathy, dilated cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy, or coronary artery disease with resultant ischemic cardiomyopathy). In some examples, a subject method is useful to treat individuals having a cardiac or cardiovascular disease or disorder, for example, cardiovascular disease, aneurysm, angina, arrhythmia, atherosclerosis, cerebrovascular accident (stroke), cerebrovascular disease, congenital heart disease, congestive heart failure, myocarditis, valve disease coronary, artery disease dilated, diastolic dysfunction, endocarditis, high blood pressure (hypertension), cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy, coronary artery disease with resultant ischemic cardiomyopathy, mitral valve prolapse, myocardial infarction (heart attack), or venous thromboembolism.

Subjects suitable for treatment using the compositions, cells and methods of the present disclosure include individuals (e.g., mammalian subjects, such as humans, non-human primates, domestic mammals, experimental non-human mammalian subjects such as mice, rats, etc.) having a cardiac condition including but limited to a condition that results in ischemic heart tissue (e.g., individuals with coronary artery disease) and the like.

In some examples, an individual suitable for treatment suffers from a cardiac or cardiovascular disease or condition, e.g., cardiovascular disease, aneurysm, angina, arrhythmia, atherosclerosis, cerebrovascular accident (stroke), cerebrovascular disease, congenital heart disease, congestive heart failure, myocarditis, valve disease coronary, artery disease dilated, diastolic dysfunction, endocarditis, high blood pressure (hypertension), cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy, coronary artery disease with resultant ischemic cardiomyopathy, mitral valve prolapse, myocardial infarction (heart attack), or venous thromboembolism. In some examples, individuals suitable for treatment with a subject method include individuals who have a degenerative muscle disease, e.g., familial cardiomyopathy, dilated cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy, or coronary artery disease with resultant ischemic cardiomyopathy.

For example, the cardiac pathology can be selected from the group consisting of congestive heart failure, myocardial infarction, cardiac ischemia, myocarditis and arrhythmia. In some embodiments, the subject is diabetic. In some embodiments, the subject is non-diabetic. In some embodiments, the subject suffers from diabetic cardiomyopathy.

For therapy, the rAAV virions of the disclosure and/or pharmaceutical compositions thereof can be administered locally or systemically. An rAAV virion can be introduced by injection, catheter, implantable device, or the like. An rAAV virion can be administered in any physiologically acceptable excipient or carrier that does not adversely affect the cells. For example, rAAV virions of the disclosure and/or pharmaceutical compositions thereof can be administered intravenously or through an intracardiac route (e.g., epicardially or intramyocardially). Methods of administering rAAV virions of the disclosure and/or pharmaceutical compositions thereof to subjects, particularly human subjects include injection or infusion of the pharmaceutical compositions (e.g., compositions comprising rAAV virions). Injection may include direct muscle injection and infusion may include intravascular infusion. The rAAV virions or pharmaceutical compositions can be inserted into a delivery device which facilitates introduction by injection into the subjects. Such delivery devices include tubes, e.g., catheters, for injecting cells and fluids into the body of a recipient subject. The tubes can additionally include a needle, e.g., a syringe, through which the cells of the invention can be introduced into the subject at a desired location.

In some embodiments, the rAAV virion is administered by subcutaneous, intravenous, intramuscular, intraperitoneal, or intracardiac injection or by intracardiac catheterization. In some embodiments, the rAAV virion is administered by direct intramyocardial injection or transvascular administration. In some embodiments, the rAAV virion is administered by direct intramyocardial injection, antegrade intracoronary injection, retrograde injection, transendomyocardial injection, or molecular cardiac surgery with recirculating delivery (MCARD).

The rAAV virions can be inserted into such a delivery device, e.g., a syringe, in different forms. The rAAV virion can be supplied in the form of a pharmaceutical composition. Such a composition can include an isotonic excipient prepared under sufficiently sterile conditions for human administration. For general principles in medicinal formulation, the reader is referred to Cell Therapy: Stem Cell Transplantation, Gene Therapy, and Cellular Immunotherapy, by G. Morstyn & W. Sheridan eds, Cambridge University Press, 1996; and Hematopoietic Stem Cell Therapy, E. D. Ball, J. Lister & P. Law, Churchill Livingstone, 2000. The choice of the excipient and any accompanying constituents of the composition can be adapted to optimize administration by the route and/or device employed.

Recombinant AAV may be administered locally or systemically. Recombinant AAV may be engineered to target specific cell types by selecting the appropriate capsid protein of the disclosure. To determine the suitability of various therapeutic administration regimens and dosages of AAV virion compositions, the rAAV virionscan first be tested in a suitable animal model. At one level, recombinant AAV are assessed for their ability to infect target cells in vivo. Recombinant AAV can also be assessed to ascertain whether it migrates to target tissues, whether they induce an immune response in the host, or to determine an appropriate number, or dosage, of rAAV virions to be administered. It may be desirable or undesirable for the recombinant AAV to generate an immune response, depending on the disease to be treated. Generally, if repeated administration of a virion is required, it will be advantageous if the virion is not immunogenic. For testing purposes, rAAV virion compositions can be administered to immunodeficient animals (such as nude mice, or animals rendered immunodeficient chemically or by irradiation). Target tissues or cells can be harvested after a period of infection and assessed to determine if the tissues or cells have been infected and if the desired phenotype (e.g. induced cardiomyocyte) has been induced in the target tissue or cells.

Recombinant AAV virions can be administered by various routes, including without limitation direct injection into the heart or cardiac catetherization. Alternatively, the rAAV virions can be administered systemically such as by intravenous infusion. When direct injection is used, it may be performed either by open-heart surgery or by minimally invasive surgery. In some embodiments, the recombinant viruses are delivered to the pericardial space by injection or infusion. Injected or infused recombinant viruses can be traced by a variety of methods. For example, recombinant AAV labeled with or expressing a detectable label (such as green fluorescent protein, or beta-galactosidase) can readily be detected. The recombinant AAV may be engineered to cause the target cell to express a marker protein, such as a surface-expressed protein or a fluorescent protein. Alternatively, the infection of target cells with recombinant AAV can be detected by their expression of a cell marker that is not expressed by the animal employed for testing (for example, a human-specific antigen when injecting cells into an experimental animal). The presence and phenotype of the target cells can be assessed by fluorescence microscopy (e.g., for green fluorescent protein, or beta-galactosidase), by immunohistochemistry (e.g., using an antibody against a human antigen), by ELISA (using an antibody against a human antigen), or by RT-PCR analysis using primers and hybridization conditions that cause amplification to be specific for RNA indicative of a cardiac phenotype.

Pharmaceutical Compostions

The present disclosure provides pharmaceutical composition comprising an rAAV virion of the disclosure. The pharmaceutical composition may include one or more of a pharmaceutically acceptable carrier, diluent, excipient, and buffer. In some embodiments, the pharmaceutically acceptable carrier, diluent, excipient, or buffer is suitable for use in a human. Such excipients, carriers, diluents, and buffers include any pharmaceutical agent that can be administered without undue toxicity. Pharmaceutically acceptable excipients include, but are not limited to, liquids such as water, saline, glycerol and ethanol. Pharmaceutically acceptable salts can be included therein, for example, mineral acid salts such as hydrochlorides, hydrobromides, phosphates, sulfates, and the like; and the salts of organic acids such as acetates, propionates, malonates, benzoates, and the like. Additionally, auxiliary substances, such as pH buffering substances may be present in such vehicles. A wide variety of pharmaceutically acceptable excipients are known in the art and need not be discussed in detail herein. Pharmaceutically acceptable excipients have been amply described in a variety of publications, including, for example, A. Gennaro (2000) Remington: The Science and Practice of Pharmacy, 20th edition, Lippincott, Williams, & Wilkins; Pharmaceutical Dosage Forms and Drug Delivery Systems (1999) H. C. Ansel et al., eds., 7^(th) ed., Lippincott, Williams, & Wilkins; and Handbook of Pharmaceutical Excipients (2000) A. H. Kibbe et al., eds., 3^(rd) ed. Amer. Pharmaceutical Assoc.

To prepare the composition, rAAV virion is generated and purified as necessary or desired. The rAAV can be mixed with or suspended in a pharmaceutically acceptable carrier.

These rAAV can be adjusted to an appropriate concentration, and optionally combined with other agents. The concentration of rAAV virion and/or other agent included in a unit dose can vary widely. The dose and the number of administrations can be optimized by those skilled in the art. For example, about 10²-10¹⁰ vector genomes (vg) may be administered. In some embodiments, the dose be at least about 10² vg, about 10³ vg, about 10⁴ vg, about 10⁵ vg, about 10⁶ vg, about 10⁷ vg, about 10⁸ vg, about 10⁹ vg, about 10¹⁰ vg, or more vector genomes. Daily doses of the compounds can vary as well. Such daily doses can range, for example, from at least about 10² vg/day, about 10³ vg/day, about 10⁴ vg/day, to about 10⁵ vg/day, about 10⁶ vg/day, about 10⁷ vg/day, about 10⁸ vg/day, about 10⁹ vg/day, about 10¹⁰ vg/day, or more vector genomes per day.

In certain embodiments, the method of treatment is enhanced by the administration of one or more anti-inflammatory agents, e.g., an anti-inflammatory steroid or a nonsteroidal antiinflammatory drug (NSAID).

Anti-inflammatory steroids for use in the invention include the corticosteroids, and in particular those with glucocorticoid activity, e.g., dexamethasone and prednisone. Nonsteroidal anti-inflammatory drugs (NSAIDs) for use in the invention generally act by blocking the production of prostaglandins that cause inflammation and pain, cyclooxygenase-1 (COX-1) and/or cyclooxygenase-2 (COX-2). Traditional NSAIDs work by blocking both COX-1 and COX-2. The COX-2 selective inhibitors block only the COX-2 enzyme. In certain embodiment, the NSAID is a COX-2 selective inhibitor, e.g., celecoxib (Celebrex®), rofecoxib (Vioxx), and valdecoxib (B extra). In certain embodiments, the anti-inflammatory is an NSAID prostaglandin inhibitor, e.g., Piroxicam.

The amount of rAAV virion for use in treatment will vary not only with the particular carrier selected but also with the route of administration, the nature of the condition being treated and the age and condition of the patient. Ultimately, the attendant health care provider may determine proper dosage. A pharmaceutical composition may be formulated with the appropriate ratio of each compound in a single unit dosage form for administration with or without cells. Cells or vectors can be separately provided and either mixed with a liquid solution of the compound composition, or administered separately.

Recombinant AAV can be formulated for parenteral administration (e.g., by injection, for example, bolus injection or continuous infusion) and may be presented in unit dosage form in ampoules, prefilled syringes, small volume infusion containers or multi-dose containers with an added preservative. The pharmaceutical compositions can take the form of suspensions, solutions, or emulsions in oily or aqueous vehicles, and can contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Suitable carriers include saline solution, phosphate buffered saline, and other materials commonly used in the art.

The compositions can also contain other ingredients such as agents useful for treatment of cardiac diseases, conditions and injuries, such as, for example, an anticoagulant (e.g., dalteparin (fragmin), danaparoid (orgaran), enoxaparin (lovenox), heparin, tinzaparin (innohep), and/or warfarin (coumadin)), an antiplatelet agent (e.g., aspirin, ticlopidine, clopidogrel, or dipyridamole), an angiotensin-converting enzyme inhibitor (e.g., Benazepril (Lotensin), Captopril (Capoten), Enalapril (Vasotec), Fosinopril (Monopril), Lisinopril (Prinivil, Zestril), Moexipril (Univasc), Perindopril (Aceon), Quinapril (Accupril), Ramipril (Altace), and/or Trandolapril (Mavik)), angiotensin II receptor blockers (e.g., Candesartan (Atacand), Eprosartan (Teveten), Irbesartan (Avapro), Losartan (Cozaar), Telmisartan (Micardis), and/or Valsartan (Diovan)), a beta blocker (e.g., Acebutolol (Sectral), Atenolol (Tenormin), Betaxolol (Kerlone), Bisoprolol/hydrochlorothiazide (Ziac), Bisoprolol (Zebeta), Carteolol (Cartrol), Metoprolol (Lopressor, Toprol XL), Nadolol (Corgard), Propranolol (Inderal), Sotalol (Betapace), and/or Timolol (Blocadren)), Calcium Channel Blockers (e.g., Amlodipine (Norvasc, Lotrel), Bepridil (Vascor), Diltiazem (Cardizem, Tiazac), Felodipine (Plendil), Nifedipine (Adalat, Procardia), Nimodipine (Nimotop), Nisoldipine (Sular), Verapamil (Calan, Isoptin, Verelan), diuretics (e.g, Amiloride (Midamor), Bumetanide (Bumex), Chlorothiazide (Diuril), Chlorthalidone (Hygroton), Furosemide (Lasix), Hydrochlorothiazide (Esidrix, Hydrodiuril), Indapamide (Lozol) and/or Spironolactone (Aldactone)), vasodilators (e.g., Isosorbide dinitrate (Isordil), Nesiritide (Natrecor), Hydralazine (Apresoline), Nitrates and/or Minoxidil), statins, nicotinic acid, gemfibrozil, clofibrate, Digoxin, Digitoxin, Lanoxin, or any combination thereof.

Additional agents can also be included such as antibacterial agents, antimicrobial agents, anti-viral agents, biological response modifiers, growth factors; immune modulators, monoclonal antibodies and/or preservatives. The compositions of the invention may also be used in conjunction with other forms of therapy.

The rAAV virions described herein can be administered to a subject to treat a disease or disorder. Such a composition may be in a single dose, in multiple doses, in a continuous or intermittent manner, depending, for example, upon the recipient's physiological condition, whether the purpose of the administration is in response to traumatic injury or for more sustained therapeutic purposes, and other factors known to skilled practitioners. The administration of the compounds and compositions of the invention may be essentially continuous over a preselected period of time or may be in a series of spaced doses. Both local and systemic administration is contemplated. In some embodiments, localized delivery of rAAV virion is achieved. In some embodiments, localized delivery of rAAV virions is used to generate a population of cells within the heart. In some embodiments, such a localized population operates as “pacemaker cells” for the heart. In some embodiments, the rAAV virions are used to generate, regenerate, repair, replace, and/or rejunevate one or more of a sinoatrial (SA) node, an atrioventricular (AV) node, a bindle of His, and/or Purkinje fibres.

To control tonicity, an aqueous pharmaceutical composition can comprise a physiological salt, such as a sodium salt. Sodium chloride (NaCl) is preferred, which may be present at between 1 and 20 mg/ml. Other salts that may be present include potassium chloride, potassium dihydrogen phosphate, disodium phosphate dehydrate, magnesium chloride and calcium chloride.

Compositions may include one or more buffers. Typical buffers include: a phosphate buffer; a Tris buffer; a borate buffer; a succinate buffer; a histidine buffer; or a citrate buffer. Buffers will typically be included at a concentration in the 5-20 mM range. The pH of a composition will generally be between 5 and 8, and more typically between 6 and 8 e.g. between 6.5 and 7.5, or between 7.0 and 7.8.

The composition is preferably sterile. The composition is preferably gluten free. The composition is preferably non-pyrogenic.

In some embodiments, a composition comprising cells may include a cryoprotectant agent. Non-limiting examples of cryoprotectant agents include a glycol (e.g., ethylene glycol, propylene glycol, and glycerol), dimethyl sulfoxide (DMSO), formamide, sucrose, trehalose, dextrose, and any combinations thereof.

One or more of the following types of compounds can also be present in the composition with the rAAV virions: a WNT agonist, a GSK3 inhibitor, a TGF-beta signaling inhibitor, an epigenetic modifier, LSD1 inhibitor, an adenylyl cyclase agonist, or any combination thereof.

Kits

A variety of kits are described herein that include any of composition (e.g. rAAV virions) described herein. The kit can include any of compositions described herein, either mixed together or individually packaged, and in dry or hydrated form. The rAAV virions and/or other agents described herein can be packaged separately into discrete vials, bottles or other containers. Alternatively, any of the rAAV virions and/or agents described herein can be packaged together as a single composition, or as two or more compositions that can be used together or separately. The compounds and/or agents described herein can be packaged in appropriate ratios and/or amounts to facilitate conversion of selected cells across differentiation boundaries to form cardiac progenitor cells and/or cardiomyocytes.

The kit can include instructions for administering those compositions, compounds and/or agents. Such instructions can provide the information described throughout this application. The rAAV virion or pharmaceutical composition can be provided within any of the kits in the form of a delivery device. Alternatively a delivery device can be separately included in the kits, and the instructions can describe how to assemble the delivery device prior to administration to a subject.

Any of the kits can also include syringes, catheters, scalpels, sterile containers for sample or cell collection, diluents, pharmaceutically acceptable carriers, and the like. The kits can provide other factors such as any of the supplementary factors or drugs described herein for the compositions in the preceding section or other parts of the application.

NUMBERED EMBODIMENTS

Embodiment I-1. A recombinant adeno-associated virus (rAAV) virion, comprising:

a) an AAV5 capsid protein, wherein the capsid protein comprises an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence; and

b) a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product.

Embodiment I-2. The rAAV virion of embodiment I-1, wherein the rAAV virion exhibits increased transduction efficiency in cardiac cells compared to an AAV virion comprising the parental sequence.

Embodiment I-3. The rAAV virion of embodiment I-1, wherein the rAAV virion exhibits increased transduction efficiency in human cardiac fibroblast (hCF) cells compared to an AAV virion comprising the parental sequence.

Embodiment I-4. The rAAV virion of embodiment I-3, wherein the rAAV virion exhibits at least 10-fold increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 1,000.

Embodiment I-5. The rAAV virion of embodiment I-3, wherein the rAAV virion exhibits at least 2-fold increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 100,000.

Embodiment I-6. The rAAV virion of embodiment I-1, wherein the rAAV virion exhibits increased transduction efficiency in induced pluripotent stem cell-derived cardiomyocyte (iPS-CM) cells compared to an AAV virion comprising the parental sequence.

Embodiment I-7. The rAAV virion of embodiment I-6, wherein the rAAV virion exhibits at least 2-fold increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 100,000.

Embodiment I-8. The rAAV virion of embodiment I-6, wherein the rAAV virion exhibits at least 4-fold increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 1,000.

Embodiment I-9. The rAAV virion of embodiment I-1, wherein the rAAV virion exhibits increased selectivity of the rAAV virion for hCF cells over iPS-CM cells.

Embodiment I-10. The rAAV virion of embodiment I-1, wherein the rAAV virion exhibits increased selectivity of the rAAV virion for iPS-CM cells over hCF cells.

Embodiment I-11. The rAAV virion of embodiment I-1, wherein the insertion site is between any two, optionally adjacent, amino acids at positions in the parental sequence corresponding to 560 to 594 of SEQ ID NO: 1.

Embodiment I-12. The rAAV virion of embodiment I-11, wherein the insertion site is between adjacent amino acids in the parental sequence corresponding to 574 and 575 of SEQ ID NO: 1.

Embodiment I-13. The rAAV virion of embodiment I-12, wherein the insertion is a peptide of formula:

-X₀-(X)_(n)-X₁₀-

wherein n is 5-9, and

wherein X₀ and X₁₀ are each independently A, S, G, or absent (SEQ ID NO: 1101).

Embodiment I-14. The rAAV virion of embodiment I-12, wherein the insertion is a peptide of formula:

-X₀-X₁-X₂-X₃-X₄-X₅-X₆-X₇-X₈-

wherein X₀ and X₈ are each independently A, S, G, or absent (SEQ ID NO: 1102).

Embodiment I-15. The rAAV virion of embodiment I-12, wherein the insertion is a peptide of formula:

-A-X₁-X₂-X₃-X₄-X₅-X₆-X₇-A-

wherein:

a) X₁ is P, R, or G;

b) X₂ is K, L, or R;

c) X₃ is any amino acid;

d) X₄ is N, H, K, or Q;

e) X₅ is any amino acid, or optionally X₅ is G, K, or S;

f) X₆ is any amino acid, or optionally X₆ is T or V; and

g) X₇ is any amino acid, or optionally X₇ is K or V (SEQ ID NO: 1103).

Embodiment I-Embodiment I-16. The rAAV virion of embodiment I-14, wherein the insertion comprises an amino acid sequence selected from SEQ ID NOs: 101-600.

Embodiment I-17. The rAAV virion of embodiment I-14, wherein the insertion comprises an amino acid sequence selected from RKVHIEV (SEQ ID NO: 81), RKYQSDL (SEQ ID NO: 82), PLTNTVK (SEQ ID NO: 83), LKYHGPP (SEQ ID NO: 84), RKYQGDM (SEQ ID NO: 85), RKFHSTD (SEQ ID NO: 86), RKHHGLE (SEQ ID NO: 87), PGTNVTK (SEQ ID NO: 88), RKMHMPD (SEQ ID NO: 89), PLKKIVQ (SEQ ID NO: 90), PLGKKTS (SEQ ID NO: 91), PRGVKVT (SEQ ID NO: 92), PLAKSKS (SEQ ID NO: 93), PRTKGAV (SEQ ID NO: 94), and PSGRKAT (SEQ ID NO: 95).

Embodiment I-18. The rAAV virion of embodiment I-14, wherein the insertion comprises an amino acid sequence selected from ARKVHIEVA (SEQ ID NO: 101), ARKYQSDLA (SEQ ID NO: 102), APLTNTVKA (SEQ ID NO: 103), ALKYHGPPA (SEQ ID NO: 104), ARKYQGDMA (SEQ ID NO: 105), ARKFHSTDA (SEQ ID NO: 106), ARKHHGLEA (SEQ ID NO: 107), APGTNVTKA (SEQ ID NO: 108), ARKMHMPDA (SEQ ID NO: 109), APLKKIVQA (SEQ ID NO: 110), APLGKKTSA (SEQ ID NO: 111), APRGVKVTA (SEQ ID NO: 112), APLAKSKSA (SEQ ID NO: 113), APRTKGAVA (SEQ ID NO: 114), APSGRKATA (SEQ ID NO: 115).

Embodiment I-19. The rAAV virion of embodiment I-14, wherein the insertion comprises the amino acid sequence PLTNTVK (SEQ ID NO: 83) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLTNTVK (SEQ ID NO: 83).

Embodiment I-20. The rAAV virion of embodiment I-14, wherein the insertion comprises the amino acid sequence PLKKIVQ (SEQ ID NO: 90) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLKKIVQ (SEQ ID NO: 90).

Embodiment I-21. An AAV5 capsid protein, wherein the capsid protein comprises an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence.

Embodiment I-22. The AAV5 capsid protein of embodiment I-21, wherein the AAV5 capsid protein exhibits increased transduction efficiency in cardiac cells compared to an AAV virion comprising the parental sequence.

Embodiment I-23. The AAV5 capsid protein of embodiment I-21, wherein the AAV5 capsid protein exhibits increased transduction efficiency in human cardiac fibroblast (hCF) cells compared to an AAV virion comprising the parental sequence.

Embodiment I-24. The AAV5 capsid protein of embodiment I-23, wherein the AAV5 capsid protein exhibits at least 10-fold increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 1,000.

Embodiment I-25. The AAV5 capsid protein of embodiment I-23, wherein The AAV5 capsid protein exhibits at least 2-fold increased transduction efficiency in hCF cells at a multiplicity of infection (MOI) of 100,000.

Embodiment I-26. The AAV5 capsid protein of embodiment I-21, wherein the AAV5 capsid protein exhibits increased transduction efficiency in induced pluripotent stem cell-derived cardiomyocyte (iPS-CM) cells compared to an AAV virion comprising the parental sequence.

Embodiment I-27. The AAV5 capsid protein of embodiment I-26, wherein the AAV5 capsid protein exhibits at least 2-fold increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 100,000.

Embodiment I-28. The AAV5 capsid protein of embodiment I-26, wherein the AAV5 capsid protein exhibits at least 4-fold increased transduction efficiency in iPS-CM cells at a multiplicity of infection (MOI) of 1,000.

Embodiment I-29. The AAV5 capsid protein of embodiment I-21, wherein the AAV5 capsid protein exhibits increased selectivity of The AAV5 capsid protein for hCF cells over iPS-CM cells.

Embodiment I-30. The AAV5 capsid protein of embodiment I-21, wherein the AAV5 capsid protein exhibits increased selectivity of The AAV5 capsid protein for iPS-CM cells over hCF cells.

Embodiment I-31. The AAV5 capsid protein of embodiment I-21, wherein the insertion site is between any two, optionally adjacent, amino acids at positions in the parental sequence corresponding to 560 to 594 of SEQ ID NO: 1.

Embodiment I-32. The AAV5 capsid protein of embodiment I-21, wherein the insertion site is between adjacent amino acids in the parental sequence corresponding to 574 and 575 of SEQ ID NO: 1.

Embodiment I-33. The AAV5 capsid protein of embodiment I-32, wherein the insertion is a peptide of formula:

-X₀-(X)_(n)-X₁₀-

wherein n is 5-9, and

wherein X₀ and X₁₀ are each independently A, S, G, or absent (SEQ ID NO: 1101).

Embodiment I-34. The AAV5 capsid protein of embodiment I-32, wherein the insertion is a peptide of formula:

-X₀-X₁-X₂-X₃-X₄-X₅-X₆-X₇-X₈-

wherein X₀ and X₈ are each independently A, S, G, or absent (SEQ ID NO: 1102).

Embodiment I-35. The AAV5 capsid protein of embodiment I-32, wherein the insertion is a peptide of formula:

-A-X₁-X₂-X₃-X₄-X₅-X₆-X₇-A-

wherein:

a) X₁ is P, R, or G;

b) X₂ is K, L, or R;

c) X₃ is any amino acid;

d) X₄ is N, H, K, or Q;

e) X₅ is any amino acid, or optionally X₅ is G, K, or S;

f) X₆ is any amino acid, or optionally X₆ is T or V; and

g) X₇ is any amino acid, or optionally X₇ is K or V (SEQ ID NO: 1103).

Embodiment I-36. The AAV5 capsid protein of embodiment I-34, wherein the insertion comprises an amino acid sequence selected from SEQ ID NOs: 101-600.

Embodiment I-37. The AAV5 capsid protein of embodiment I-34, wherein the insertion comprises an amino acid sequence selected from RKVHIEV (SEQ ID NO: 81), RKYQSDL (SEQ ID NO: 82), PLTNTVK (SEQ ID NO: 83), LKYHGPP (SEQ ID NO: 84), RKYQGDM (SEQ ID NO: 85), RKFHSTD (SEQ ID NO: 86), RKHHGLE (SEQ ID NO: 87), PGTNVTK (SEQ ID NO: 88), RKMHMPD (SEQ ID NO: 89), PLKKIVQ (SEQ ID NO: 90), PLGKKTS (SEQ ID NO: 91), PRGVKVT (SEQ ID NO: 92), PLAKSKS (SEQ ID NO: 93), PRTKGAV (SEQ ID NO: 94), and PSGRKAT (SEQ ID NO: 95).

Embodiment I-38. The AAV5 capsid protein of embodiment I-34, wherein the insertion comprises an amino acid sequence selected from ARKVHIEVA (SEQ ID NO: 101), ARKYQSDLA (SEQ ID NO: 102), APLTNTVKA (SEQ ID NO: 103), ALKYHGPPA (SEQ ID NO: 104), ARKYQGDMA (SEQ ID NO: 105), ARKFHSTDA (SEQ ID NO: 106), ARKHHGLEA (SEQ ID NO: 107), APGTNVTKA (SEQ ID NO: 108), ARKMHMPDA (SEQ ID NO: 109), APLKKIVQA (SEQ ID NO: 110), APLGKKTSA (SEQ ID NO: 111), APRGVKVTA (SEQ ID NO: 112), APLAKSKSA (SEQ ID NO: 113), APRTKGAVA (SEQ ID NO: 114), APSGRKATA (SEQ ID NO: 115).

Embodiment I-39. The AAV5 capsid protein of embodiment I-34, wherein the insertion comprises the amino acid sequence PLTNTVK (SEQ ID NO: 83) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLTNTVK (SEQ ID NO: 83).

Embodiment I-40. The AAV5 capsid protein of embodiment I-34, wherein the insertion comprises the amino acid sequence PLKKIVQ (SEQ ID NO: 90) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLKKIVQ (SEQ ID NO: 90).

Embodiment I-41. A polynucleotide encoding the AAV5 capsid protein of any one of embodiments I-21 to I-40.

Embodiment I-42. A pharmaceutical composition comprising the rAAV virion of any one of embodiments I-1 to I-20.

Embodiment I-43. A method of transducing a cardiac cell, comprising contacting the cardiac cell with an rAAV virion according to any one of embodiments I-1 to I-20, wherein the rAAV virion transduces the cardiac cell.

Embodiment I-44. A method of delivering one or more gene products to a cardiac cell, comprising contacting the cardiac cell with an rAAV virion according to any one of embodiments I-1 to I-20, wherein the cardiac cell expresses the gene product.

Embodiment I-45. The method of embodiment I-44, wherein the one or more gene products comprise a short-hairpin RNA or a microRNA.

Embodiment I-46. The method of embodiment I-44, wherein the one or more gene products comprising a guide RNA, a Cas protein, and optionally a repair template, wherein the gene products form a functional a CRISPR/Cas system.

Embodiment I-47. The method of embodiment I-44, wherein the one or more gene products comprise a polypeptide.

Embodiment I-48. The method of embodiment I-47, wherein the polypeptide is selected from cardiac troponin T; a cardiac sarcomeric protein; β-myosin heavy chain; myosin ventricular essential light chain 1; myosin ventricular regulatory light chain 2; cardiac α-actin; a-tropomyosin; cardiac troponin I; cardiac myosin binding protein C; four-and-a-half LIM protein 1; titin; 5-AMP-activated protein kinase subunit gamma-2; troponin I type 3, myosin light chain 2, actin alpha cardiac muscle 1; cardiac LIM protein; caveolin 3 (CAV3); galactosidase alpha (GLA); lysosomal-associated membrane protein 2 (LAMP2); mitochondrial transfer RNA glycine (MTTG); mitochondrial transfer RNA isoleucine (MTTI); mitochondrial transfer RNA lysine (MTTK); mitochondrial transfer RNA glutamine (MTTQ); myosin light chain 3 (MYL3); troponin C (TNNC1); transthyretin (TTR); sarcoendoplasmic reticulum calcium-ATPase 2a (SERCA2a); stromal-derived factor-1 (SDF-1); adenylate cyclase-6 (AC6); β-ARKct (β-adrenergic receptor kinase C terminus); fibroblast growth factor (FGF); platelet-derived growth factor (PDGF); vascular endothelial growth factor (VEGF); hepatocyte growth factor; hypoxia inducible growth factor; thymosin beta 4 (TMSB4X); nitric oxide synthase-3 (NOS3); apoplipoprotein-E (ApoE); and superoxide dismutase (SOD); S100A1

Embodiment I-49. The method of embodiment I-44, wherein the one or more gene products comprise one or more reprogramming factors.

Embodiment I-50. The method of embodiment I-49, wherein the one or more reprogramming factors is one or more polypeptide selected from ASCL1, MYOCD, MEF2C, TBX5, CCNB1, CCND1, CDK1, CDK4, AURKB, OCT4, BAF60C, ESRRG, GATA4, GATA6, HAND2, IRX4, ISLL, MESP1, MESP2, NKX2.5, SRF, TBX20, and ZFPM2.

Embodiment I-51. The method of any one of embodiments I-43 to I-50, wherein the method reprograms the cardiac cell into a cardiac cardiomyocyte.

Embodiment I-52. A method of treating a cardiac pathology in a subject in need thereof, comprising administering a therapeutically effective amount of a pharmaceutical composition according to embodiment I-42 to the subject, wherein the rAAV virion transduces cardiac tissue.

Embodiment I-53. The method of embodiment I-52, wherein the rAAV virion is administered by subcutaneous, intravenous, epicardial, intramuscular, intraperitoneal, or intracardiac injection or by intracardiac catheterization.

Embodiment I-54. The method of embodiment I-52, wherein the rAAV virion is administered by direct intramyocardial injection or transvascular administration.

Embodiment I-55. The method of embodiment I-52, wherein the rAAV virion is administered by direct intramyocardial injection, antegrade intracoronary injection, retrograde injection, transendomyocardial injection, or molecular cardiac surgery with recirculating delivery (MCARD).

Embodiment I-56. A method of identifying AAV capsid proteins that confer on rAAV virions increased transduction efficiency in target cells, comprising:

a) providing a population of rAAV virions whose rAAV genomes comprise a library of cap polynucleotides encoding variant AAV capsid proteins;

b) contacting the population with target cells for a time sufficient to permit transduction of the cap polynucleotide into the target cells by the rAAV virions; and

c) sequencing the cap polynucleotides from the target cells, thereby identifying AAV capsid proteins that confer increased transduction efficiency in the target cells.

Embodiment I-57. The method of embodiment I-56, further comprising, before step (b), depleting the population of rAAV virions by contacting the population with non-target cells for time sufficient to permit attachment of the rAAV virions to the non-target cells.

Embodiment I-58. A recombinant adeno-associated virus (rAAV) virion, comprising:

a) an AAV5 capsid protein, wherein the capsid protein comprises one or more substitutions selected from S651A, T578A, or T582A compared to a parental AAV5 capsid; and

b) a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product.

Embodiment I-59. The rAAV virion of embodiment I-58, wherein the AAV5 capsid protein comprises two or more substitutions selected from S651A, T578A, or T582A.

Embodiment I-60. The rAAV virion of embodiment I-58, wherein the AAV5 capsid protein comprises T582A and S651A substitutions.

Embodiment I-61. The rAAV virion of embodiment I-58, wherein the AAV5 capsid protein comprises T578A and T582A substitutions.

Embodiment I-62. The rAAV virion of embodiment I-58, wherein the AAV5 capsid protein comprises T578A and S651A substitutions.

Embodiment I-63. The rAAV virion of embodiment I-58, wherein the AAV5 capsid protein comprises S651A, T578A, and T582A substitutions.

Embodiment I-64. The rAAV virion of any one of embodiments I-58 to I-62, wherein the AAV5 capid protein shares at least 95% identity to SEQ ID NO: 73.

Embodiment I-65. The rAAV virion of any one of embodiments I-58 to I-62, wherein the AAV5 capid protein shares at least 98% identity to SEQ ID NO: 73.

Embodiment I-66. The rAAV virion of any one of embodiments I-58 to I-62, wherein the AAV5 capid protein shares at least 99% identity to SEQ ID NO: 73.

Embodiment I-67. The rAAV virion of any one of embodiments I-58 to I-62, wherein the AAV5 capid protein comprises the polypeptide sequence SEQ ID NO: 73.

Embodiment I-68. An AAV5 capsid protein comprising one or more substitutions selected from S651A, T578A, or T582A compared to a parental AAV5 capsid.

Embodiment I-69. The AAV5 capsid protein of embodiment I-67, wherein the capsid protein comprises two or more substitutions selected from S651A, T578A, or T582A.

Embodiment I-70. The AAV5 capsid protein of embodiment I-67, wherein the capsid protein comprises T582A and S651A substitutions.

Embodiment I-71. The AAV5 capsid protein of embodiment I-68, wherein the capsid protein comprises T578A and T582A substitutions.

Embodiment I-72. The AAV5 capsid protein of embodiment I-68, wherein the capsid protein comprises T578A and S651A substitutions.

Embodiment I-73. The AAV5 capsid protein of embodiment I-68, wherein the capsid protein comprises S651A, T578A, and T582A substitutions.

Embodiment I-74. The AAV5 capsid protein of any one of embodiments I-68 to I-73, wherein the capid protein shares at least 90% identity to SEQ ID NO: 73.

Embodiment I-75. The AAV5 capsid protein of any one of embodiments I-68 to I-73, wherein the capid protein shares at least 95% identity to SEQ ID NO: 73.

Embodiment I-76. The AAV5 capsid protein of any one of embodiments I-68 to I-73, wherein the capid protein shares at least 98% identity to SEQ ID NO: 73.

Embodiment I-77. The AAV5 capsid protein of any one of embodiments I-68 to I-73, wherein the capid protein shares at least 99% identity to SEQ ID NO: 73.

Embodiment I-78. A polynucleotide encoding the AAV5 capsid protein of any one of embodiments I-68 to I-77.

Embodiment I-79. A pharmaceutical composition comprising the rAAV virion of any one of embodiments I-58 to I-67.

Embodiment I-80. A method of transducing a cardiac cell, comprising contacting the cardiac cell with an rAAV virion according to any one of embodiments I-58 to I-67, wherein the rAAV virion transduces the cardiac cell.

Embodiment I-81. A method of delivering one or more gene products to a cardiac cell, comprising contacting the cardiac cell with an rAAV virion according to any one of embodiments I-58 to I-67, wherein the cardiac cell expresses the gene product.

Embodiment I-82. The method of embodiment I-81, wherein the one or more gene products comprise a short-hairpin RNA or a microRNA.

Embodiment I-83. The method of embodiment I-81, wherein the one or more gene products comprising a guide RNA, a Cas protein, and optionally a repair template, wherein the gene products form a functional a CRISPR/Cas system.

Embodiment I-84. The method of embodiment I-81, wherein the one or more gene products comprise a polypeptide.

Embodiment I-85. The method of embodiment I-84, wherein the polypeptide is selected from cardiac troponin T; a cardiac sarcomeric protein; β-myosin heavy chain; myosin ventricular essential light chain 1; myosin ventricular regulatory light chain 2; cardiac α-actin; a-tropomyosin; cardiac troponin I; cardiac myosin binding protein C; four-and-a-half LIM protein 1; titin; 5-AMP-activated protein kinase subunit gamma-2; troponin I type 3, myosin light chain 2, actin alpha cardiac muscle 1; cardiac LIM protein; caveolin 3 (CAV3); galactosidase alpha (GLA); lysosomal-associated membrane protein 2 (LAMP2); mitochondrial transfer RNA glycine (MTTG); mitochondrial transfer RNA isoleucine (MTTI); mitochondrial transfer RNA lysine (MTTK); mitochondrial transfer RNA glutamine (MTTQ); myosin light chain 3 (MYL3); troponin C (TNNC1); transthyretin (TTR); sarcoendoplasmic reticulum calcium-ATPase 2a (SERCA2a); stromal-derived factor-1 (SDF-1); adenylate cyclase-6 (AC6); β-ARKct (β-adrenergic receptor kinase C terminus); fibroblast growth factor (FGF); platelet-derived growth factor (PDGF); vascular endothelial growth factor (VEGF); hepatocyte growth factor; hypoxia inducible growth factor; thymosin beta 4 (TMSB4X); nitric oxide synthase-3 (NOS3); apoplipoprotein-E (ApoE); and superoxide dismutase (SOD); S100A1

Embodiment I-86. The method of embodiment I-81, wherein the one or more gene products comprise one or more reprogramming factors.

Embodiment I-87. The method of embodiment I-86, wherein the one or more reprogramming factors is one or more polypeptide selected from ASCL1, MYOCD, MEF2C, TBX5, CCNB1, CCND1, CDK1, CDK4, AURKB, OCT4, BAF60C, ESRRG, GATA4, GATA6, HAND2, IRX4, ISLL, MESP1, MESP2, NKX2.5, SRF, TBX20, and ZFPM2.

Embodiment I-88. The method of any one of embodiments I-80 to I-87, wherein the method reprograms the cardiac cell into a cardiac cardiomyocyte.

Embodiment I-89. A method of treating a cardiac pathology in a subject in need thereof, comprising administering a therapeutically effective amount of a pharmaceutical composition according to embodiment I-79 to the subject, wherein the rAAV virion transduces cardiac tissue.

Embodiment I-89. The method of embodiment I-89, wherein the rAAV virion is administered by subcutaneous, epicardial, intravenous, intramuscular, intraperitoneal, or intracardiac injection or by intracardiac catheterization.

Embodiment I-90. The method of embodiment I-89, wherein the rAAV virion is administered by direct intramyocardial injection or transvascular administration.

Embodiment I-91. The method of embodiment I-89, wherein the rAAV virion is administered by direct intramyocardial injection, antegrade intracoronary injection, retrograde injection, transendomyocardial injection, or molecular cardiac surgery with recirculating delivery (MCARD).

The following non-limiting Examples illustrate some of the experimental work involved in developing the invention.

EXAMPLES Example 1: Identification of Capsid Protein Sequences

Library Generation and AAV Selection

A library screening strategy incorporating an initial negative selection step on induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) followed by a positive selection step on human cardiac fibroblasts (hCFs) was performed as shown in FIG. 1. Briefly, a library of cap gene sequences was generated by PCR using primers P1 (GTCGGCGGGCAGATGGCCACCAACAACCAGGCCNNKNNKNNKNNKNNKNN-KNNKGCCAGCTCCACCACTGCCCCCGCGACCGGCACG) (SEQ ID NO: 6) and P2 (TC-CCCAGCATGAGCGATGCATITTATTGAGGGTATGCGAC) (SEQ ID NO: 7) {N=A, C, G, or T; K=G or T} and cloned into NotI and NheI linearized pCR-AAV-LIB575 via Gibson assembly (FIG. 2A). pCR-AAV-LIB575 was packaged into rAAV virions using the HEK293T packaging cell line. The vector contains the rep gene of AAV2 (“Rep2”) and the cap gene of AAV (“Cap5”) flanked by 3′ and 5′ inverted terminal repeats (ITRs). The random 7-mer polypeptide library flanked by alanine residues (AXXXXXXA; SEQ ID NO: 100) is inserted at position 575 in the cap gene. FIG. 2B shows the structure of the AAV5 capsid with a black arrow indicating the insertion site indicated on one of the 60 copies of the capsid protein present on the assembled AAV virion. The insertion into the cap gene results in the same polypeptide being inserted in all 60 copies at the equivalent positions (not indicated in figure).

Virions at a multiplicity of infection ranging from 50,000 (round 1) to 1,000 (round 3) were mixed in liquid culture medium and applied to iPS-CM cells isolated from a healthy 30-year old male. Cells were incubated for 24 hours at 37° C. and 5% CO₂. DNA was isolated from the iPS-CM cells, amplified by PCR using primers P2 (SEQ ID NO: 7) and P3 (CCATCGACGTCAGACGCGGAAGCTTCGATCAACTACGCAGACAG)(SEQ ID NO: 8), and sequenced using the Oxford NanoPore MiniION according to the manufacturer's instruction. Sequencing reads for this negative selection step were analyzed (data not shown)

Culture media containing the rAAV virions that had not attached to or infected the iPS-CM cells was then transferred to to hCF cells and incubated for 24 hours at 37° C. and 5% CO₂. After 24 hours, plates were washed with culture media, the adherent hCF cells were removed, and PCR amplification of cap genes and sequencing was performed on the DNA isolated from hCF cells infected with rAAV as described above. Representative data for the starting library of sequences and for the sequences after this first round of negative and positive selection are shown in FIG. 3A and FIG. 3B, respectively. Library complexity is decreased, consistent with enrichment of selected sequences, as the percentage of unique reads decreased from 97.6% to 87.5%.

The resulting library of cap genes from the first round was subcloned into pCR-AAV-LIB575 again and the same negative and positive selection procedure was performed as round 2. This was repeated as round 3. Continued enrichment of sequences was observed by a decrease in unique reads from round 2 (FIG. 3C) to round 3 (FIG. 3D) of 58.2% to 41.5%.

Confirmation of Increased Transductions Efficiency in In Vitro System

Enrichment of reads is a experimental measurement of increased transduction efficiency, as the number of reads for each unique sequence is a correlated for increased transduction efficiency of the rAAV virion containing that insertion sequence. The 500 sequences with highest abundance are provided in Table 2 below.

The sequences listed in Table 1 were selected for re-testing in cultured hCF cells (FIGS. 4A-4D) and iPS-CM cells (FIG. 5A-5D) using a GFP reporter assay.

TABLE 1 Re-Tested Insertion Sequences Representation SEQ in hCF Library Representation Enrichment ID Variant after 3 Rounds in Parental (Fold NO: Peptide Name (%) Library (%) Increase) 101 ARKVHIEVA CR2 5.4328 0.0022 2469 102 ARKYQSDLA CR5 1.6044 0.0045  357 103 APLTNTVKA CR17 1.1055 0.0015  737 104 ALKYHGPPA CR18 0.9983 0.0015  666 105 ARKYQGDMA CR19 0.8591 0.0007 1227 106 ARKFHSTDA CR20 0.8368 0.0004 2092 107 ARKHHGLEA CR8 0.7068 0.0007 1010 108 APGTNVTKA CR21 0.6159 0.0041  150 109 ARKMHMPDA CR22 0.601 0 n/d 110 APLKKIVQA CR23 0.3165 0.0015  211 111 APLGKKTSA CR24 0.2339 0.0004  585 112 APRGVKVTA CR25 0.2223 0 n/d 113 APLAKSKSA CR26 0.1448 0.0004  362 114 APRTKGAVA CR27 0.1443 0.0004  361 115 APSGRKATA CR28 0.1146 0.0004  287 n/d = not determined

Briefly, the peptides of Table 1 were each cloned into the cap gene at the same insertion site in an Rep-Cap plasmid lacking inverted terminal repeats (ITRs), rather than in an AAV genome as in the selection experiment. These Rep-Cap plasmids were each used to express Rep2 and the respective Cap variant in order to generate rAAV packaging a reporter AAV genome (AAV2 ITRs flanking a GFP transgene controlled by a CAG promoter). The resulting rAAV virions, containing GFP transgene having the engineered capsid proteins as capsid, were plated onto adherent hCF or iPS-CM cells at on MOI of 100,000 (FIG. 4A, FIG. 5A, FIG. 5D) or 1,000 (FIG. 4D). Transduction efficiency was measured by counting GFP fluorescent cells using automated digital widefield microscopy with the Cytation 5™ cell imaging multi-mode reader. Representative fluorescent micrographs are shown in (FIG. 4B; parental AAV5 capsid—SEQ ID NO: 1) and (FIG. 4C; AAV5.CR17 capsid—SEQ ID NO: 103). Transduction efficiency of fifteen AAV5 variants in hCF cells (FIG. 4A) was benchmarked against unmodified AAV5 (right most bar). Darker bars represent sequences that resulted in increase transduction efficiency in hCF cells in this experiment.

In iPS-CM cells (FIG. 5A-5D), increased transduction frequency was also observed and in fact the fold enhancement of transduction compared to parental AAV5 was greater than in hCF cells (FIG. 5A and FIG. 5D). Representative fluorescent images are shown for hCFs transduced by either unmodified AAV5 (FIG. 5B) or AAV5.CR23 (FIG. 5C).

Testing with human cardiac fibroblast cells was then repeated in mouse cardiac fibroblast (mCF) cells at at a high (100,000) medium (10,000) or low (1,000) MOI with either AAV5.CAG-GFP or AAV5.CR17.CAG-GFP. It was observed that in addition to increased overall numbers of GFP+ cells in AAV5.CR17 versus AAV5 test, a high-intensity GFP population is formed by AAV5.CR17, but not by AAV5 (FIG. 6A). Therefore the intensity measurements for individual cells in FIGS. 6B-6E were gated into total population and high-GFP+ population cell subsets. Increased percent GFP+(FIG. 6B) and GFP intensity (FIG. 6C) were observed in the “total GFP” population when cells were transduced with AAV5.CR17 compared to unmodified AAV5 at high, medium, or low MOI. Increased percent GFP+(FIG. 6D) and GFP intensity (FIG. 6E) were also observed in the “high GFP” population when cells were transduced with AAV5.CF17 compared to unmodified AAV5. The trend in FIG. 6E was less pronounced merely because gating on high GFP+ cells selected a population of cells with high intensity GFP expression.

In Vivo Testing

The AAV5.CR17 capsid was then tested in vivo in health and disease animals. Specifically, CD-1® IGS mice sourced from Charles River® (a wild-type background) were split into health and disease groups. The diseased group was subjected to induced myocardial infarction (MI) using the ligation method of Gao et al. Circulation Research (2010) 107:1445-1453. 1.2×10¹¹ vg of either AAV5.CAG-GFP or AAV5.CR17.CAG-GFP was injected into the 6-week old CD-1 mice via an intramyocardial injection. GFP intensity and distribution was assessed 7 days following an injection. All heart tissue sections were imaged using a 20× objective with equal gain and exposure. Anti-GFP immunostaining and nuclei counterstaining with DAPI are shown. Cardiomyocytes and fibroblasts were distinguished by morphology. Increased cardiomyocyte and fibroblast transduction is observed with AAV5.CR17 in both non-MI and MI animals (FIGS. 7E-7F and FIGS. 7G-7H) compared to AAV5 (FIGS. 7A-7B and FIGS. 7C-7D).

Shared Sequence Motifs

To identify residues share among insertions that demonstrate enrichment after selection, sequence motifs were generated using all sequence data, or the top sequences after round 3. Briefly, sequence motifs were generated for the top 100 (FIG. 8A), top 50 (FIG. 8B), top 20 (FIG. 8C) sequences in Table 2, as well as for the sequences that were re-tested in vitro in this Example (FIG. 8D). A sequence motif was also generated for all sequences, using the number of reads for each sequence to weight the significance of each amino acid in the motif (FIG. 8E). The sequence motifs suggest that certain amino acids are favored as certain positions in the insertion site.

The top sequences from the library are shown below in Table 2. The flanking ‘A’ residues at the start and end of the insertion are, in some embodiments, replaced with another amino acid, such as a flexible amino acid (G or S), or be absent.

TABLE 2 Ordered List of Insertion Sequences - Top 500 after hCF round 3 SEQ ID hCF hCF HCF Myocyte Myocyte NO: Insertion Parental round1 round2 round3 round 1 round 3 101 ARKVHIEVA 6 50 2681 11706 993 4433 102 ARKYQSDLA 12 68 1368 3457 540 1181 103 APLTNTVKA 4 43 1498 2382 555 1131 104 ALKYHGPPA 4 16 639 2151 286 818 116 ARKIHLDAA 0 4 376 2004 158 1852 105 ARKYQGDMA 2 19 748 1851 346 1895 106 ARKFHSTDA 1 5 417 1803 179 1416 107 ARKHHGLEA 2 35 807 1523 316 679 108 APGTNVTKA 11 67 1256 1327 475 614 109 ARKMHMPDA 0 18 331 1295 160 406 117 APYHNATKA 6 72 1115 1177 417 258 118 ARKWHDTEA 1 14 398 1045 173 294 119 APVANVTKA 4 28 930 995 374 310 120 ARKVHIGVA 1 6 196 931 76 741 121 APLNNSVKA 8 47 755 927 244 547 122 ARRYHGSEA 0 4 217 901 87 443 123 AYGHPNVIA 11 114 981 757 425 288 124 APFTNSTKA 1 18 450 727 162 359 110 APLKKIVQA 4 32 393 682 178 51 125 ARKVQVGVA 2 13 182 602 62 319 126 AGRCILRVA 0 1 118 591 63 286 127 AKIKTGVPA 8 57 642 554 282 124 128 AWHNSYPHA 0 18 331 531 133 278 111 APLGKKTSA 1 10 165 504 55 15 129 APSVNLTKA 7 39 506 485 193 190 112 APRGVKVTA 0 10 190 479 68 32 130 APLSNLVKA 3 18 323 475 134 184 131 ARKFHTETA 0 2 90 455 42 213 132 AGRFILDAA 0 1 81 439 30 457 133 AVKQNQTKA 9 29 251 426 129 466 134 AVRSNKVAA 10 61 424 415 184 443 135 AGRCILRWA 1 2 90 412 32 116 136 ARKWQQSEA 3 1 145 407 57 164 137 APLKNGTKA 1 10 109 403 45 136 138 AGLKNAVKA 0 12 131 398 60 262 139 APAINHVKA 2 20 414 349 171 112 140 AGVLSNRIA 9 54 450 348 170 173 141 APLANTAKA 3 12 328 341 138 113 142 ARRWHGDEA 1 12 148 332 75 137 143 APLRNANKA 3 28 267 329 106 87 144 APLTNLIKA 6 22 313 329 125 130 145 ARKLQVGSA 5 10 137 327 47 160 146 AEGAYIEVA 0 0 79 320 53 85 147 APMANLVKA 1 15 254 317 120 130 113 APLAKSKSA 1 16 198 312 77 17 114 APRTKGAVA 1 7 216 311 88 22 148 AKTVNATKA 4 8 154 310 68 278 149 APVTKKASA 0 5 153 301 56 19 150 APMPNSAKA 3 13 314 290 96 152 151 AGSIQSDLA 1 2 101 275 31 122 152 ALLRNTVKA 1 12 167 271 73 242 153 AGHLSNHIA 4 25 274 263 140 107 154 APMSNRATA 1 28 305 258 120 91 155 ARKYQLDLA 1 5 107 250 40 300 115 APSGRKATA 1 4 89 247 31 5 156 APHSNSSKA 2 11 186 240 78 113 157 AGLGNAVKA 4 33 339 236 150 137 158 AGSIRGDMA 0 1 90 232 28 267 159 ALLRIRLKA 0 8 176 224 55 196 160 ARKVYIEVA 0 2 69 224 56 59 161 AWKVHIEVA 0 2 64 220 46 66 162 APRSAKPVA 2 12 163 219 72 24 163 APLANLTKA 1 5 174 217 67 58 164 APRGSAVKA 1 27 147 214 41 16 165 AGRLHIEVA 0 2 84 213 34 110 166 APLRISTKA 0 2 123 202 72 82 167 ARKWQSHEA 2 2 92 198 37 67 168 APKVHIEVA 0 0 32 192 29 42 169 ARRCILRWA 0 1 55 189 23 40 170 AKTKSGINA 4 18 126 186 66 65 171 APSINSVKA 1 11 185 184 89 108 172 APSLNLVKA 6 30 246 175 89 53 173 APLGNMTKA 0 6 122 171 47 61 174 ALYHNATKA 0 13 150 163 99 23 175 ALLSNLVKA 2 6 144 162 80 38 176 ALRHKSNNA 0 9 41 154 26 28 177 APRKSNASA 1 21 147 151 68 24 178 APFSNSSKA 1 5 105 150 46 81 179 AGRCILGVA 1 2 47 150 21 170 180 APASNSSRA 2 22 147 149 61 72 181 AGKYQSDLA 0 2 62 146 43 57 182 AGRCILEVA 0 3 32 145 19 79 183 ALTQNSTKA 5 16 183 143 69 171 184 ALIANATKA 0 12 133 143 45 74 185 ARKFHAMEA 2 4 86 141 39 195 186 APLRSTVKA 1 11 53 139 19 5 187 ARYSPNSVA 0 15 166 137 77 64 188 AGKVHIEVA 0 1 38 137 14 49 189 AGSISPDLA 0 3 52 135 21 69 190 ARKVHIEAA 0 0 34 135 32 37 191 ALRMNSVKA 0 10 79 134 46 133 192 APAHKVKAA 3 12 71 132 27 10 193 ACKHHGLEA 1 5 78 132 38 46 194 AGLSNATKA 6 30 232 131 109 121 195 APLANRTSA 5 23 215 131 86 46 196 AGRCILRCA 0 2 28 129 23 96 197 AQEDSFDAA 0 0 32 129 9 42 198 AVSIMGLEA 1 4 87 127 39 82 199 APGTNLIKA 4 7 128 126 54 60 200 ATSGNSVRA 15 53 216 124 126 146 201 ARFPVGSLA 2 11 130 124 60 74 202 APRVTKAAA 0 9 122 124 54 5 203 AGSFHSTDA 0 1 29 124 6 83 204 AHKALVHGA 3 15 131 122 56 313 205 ALLTNTVKA 0 3 92 122 33 30 206 ALLKKIVQA 0 1 88 122 48 5 207 APRDNRTSA 4 20 167 121 58 57 208 APRVNKTVA 0 20 97 121 55 19 209 AGIMSNKIA 2 5 153 121 74 68 210 ALFTNTVKA 0 4 84 119 34 39 211 APRTNITKA 1 10 60 118 20 56 212 AGSFASTDA 0 1 26 118 18 128 213 APQSNVTKA 1 12 143 116 51 38 214 AWRYHGSEA 0 0 27 116 8 28 215 APHKATKSA 1 6 71 114 31 4 216 APLTNTAKA 1 2 72 114 23 33 217 APLGNTAKA 0 4 89 111 39 39 218 APLDNRLKA 1 10 109 110 41 30 219 AGRCILSAA 0 0 37 110 2 26 220 APLINVVKA 0 7 65 109 27 57 221 AGRCILKLA 0 0 32 108 20 58 222 APISGKNKA 0 3 41 105 16 5 223 AKSKAGQVA 6 13 113 102 31 35 224 AGKIHLDAA 0 0 15 102 20 90 225 AGHTNSVKA 1 8 100 101 54 92 226 ALFTNSTKA 1 1 59 98 24 38 227 APSTNTVKA 0 1 56 98 23 17 228 ARKIHLMRA 0 0 26 98 7 41 229 APAPNSVKA 2 9 157 96 54 87 230 AGITGNKIA 0 7 111 95 55 57 231 AGRVHIEVA 0 1 33 93 14 30 232 ARKVHIEGA 0 1 28 93 8 25 233 AKKLNNSIA 0 20 106 92 60 19 234 AGSISRILA 0 0 31 91 12 23 235 AGYMGNHIA 1 15 128 90 53 24 236 AVSIMGWEA 0 0 34 90 12 27 237 AVVSNAARA 7 17 137 89 52 75 238 APRAKVVQA 1 9 109 89 38 3 239 APLGNTVRA 2 11 76 88 31 35 240 APRTTTVKA 0 8 41 88 15 5 241 APGTDVTKA 0 4 78 88 35 93 242 ALGRNVTKA 3 9 68 87 31 65 243 ALKHHGPPA 0 0 21 86 9 23 244 APLRIPTKA 0 0 63 86 20 16 245 AQATNTVRA 8 39 148 85 59 72 246 ASTGNSTRA 4 34 124 85 60 103 247 APMHNGIKA 3 13 75 85 32 48 248 ARKVHTEVA 0 0 28 85 8 23 249 AMKYHGPAA 6 9 66 84 27 30 250 ALHLNSIKA 17 25 146 83 75 57 251 APSINTIKA 1 12 138 83 61 45 252 AGRCILSVA 0 0 12 83 4 12 253 AKAKAGVAA 0 11 72 82 28 26 254 APSSNAAKA 3 6 105 82 33 20 255 ARKVQSGVA 0 4 31 82 14 25 256 AGKYQGDMA 0 1 19 82 22 87 257 AMVIPNVIA 2 16 125 81 35 54 258 AGVKHNSIA 0 8 76 81 29 38 259 ARKHQSDLA 0 2 35 81 19 28 260 AKQPNAVKA 3 1 66 81 33 45 261 AFTHPNSVA 3 11 100 80 53 58 262 APRTSTVKA 1 3 29 79 10 2 263 ARVGVKVTA 0 1 37 79 20 5 264 AEGVHIEVA 0 0 29 79 12 22 265 ASKVHIEVA 0 0 21 79 5 8 266 APLKNAISA 7 39 188 78 65 22 267 ASRNNMTKA 1 12 44 78 29 61 268 ARKVQAGVA 0 0 22 78 8 19 269 AGFTNNTKA 4 18 132 76 61 23 270 APRKVTQSA 1 16 94 76 40 10 271 APLKKGAVA 0 8 63 76 27 5 272 APGKSTAKA 2 3 43 76 18 3 273 AGRCILGCA 0 2 10 76 14 54 274 ALNINSTKA 2 9 109 75 50 65 275 APLGNGAKA 1 7 90 75 39 18 276 AGNHPNKVA 1 4 95 75 54 55 277 AKNVHPNSA 1 13 107 74 55 57 278 APLKAKTSA 0 7 73 74 20 4 279 APLQNSVKA 1 2 57 74 20 28 280 AKYKQGVSA 1 2 68 74 22 17 281 AGSGMILEA 0 1 36 74 20 11 282 ARKVHVPVA 2 16 54 73 18 42 283 ARKIQTMSA 3 15 37 73 19 30 284 ALRGNKIQA 0 8 58 73 27 50 285 APIANNTRA 2 8 75 73 32 26 286 AFHHPNAVA 0 6 76 73 34 33 287 ALKVHIEVA 0 1 15 73 9 22 288 APRGVKTTA 0 5 23 72 12 2 289 AGSFMSTDA 0 0 11 72 6 108 290 AKQIHPNSA 3 27 148 71 68 47 291 ARWRNVTKA 0 2 89 71 15 53 292 ARKYRGDMA 0 1 33 71 25 110 293 APLHNRNNA 1 13 103 70 41 19 294 APHSNRTVA 5 18 120 69 55 30 295 AGIRNVVKA 1 14 43 69 26 62 296 ARSSKPNSA 3 13 59 69 32 21 297 ARTKNGVPA 3 12 67 69 33 22 298 ARYHANSIA 0 9 65 69 23 30 299 AVRTNAVKA 0 6 37 69 14 127 300 AIVSNHSKA 8 18 104 68 45 51 301 APFDNHIRA 0 13 92 68 42 19 302 APRKPNASA 0 7 65 68 15 6 303 ARKVHIGGA 0 0 14 68 11 34 304 AKRASGPTA 2 12 88 67 44 10 305 AECESYFKA 1 2 84 67 26 23 306 APPGRKSSA 1 1 24 67 4 2 307 ARKYQGDIA 0 0 35 67 23 107 308 APITNRSTA 5 21 109 66 54 21 309 APRSVGKAA 0 12 68 66 29 12 310 ACKMHMPDA 0 2 13 66 18 18 311 APLNKKVAA 0 1 25 66 13 2 312 APIANKVSA 3 18 88 65 25 31 313 APRSGVTKA 0 10 41 65 11 5 314 AIRHPNVVA 0 9 115 65 67 42 315 APYQNIVKA 2 7 73 65 24 14 316 AFTANSTKA 0 2 53 65 22 44 317 ARKHQGDMA 0 1 34 65 9 39 318 APLRILLKA 0 1 42 65 17 32 319 AEGAHIEVA 0 0 20 65 20 30 320 AGYSNSVKA 9 23 138 64 60 80 321 APLTNRISA 1 12 83 64 35 19 322 APPHAKKNA 0 1 24 64 6 3 323 AGSFLSTDA 0 0 15 64 2 97 324 ARKYQFDLA 0 0 38 64 10 22 325 ARLRNTAKA 0 4 65 63 23 43 326 ARKMHMLDA 0 0 20 63 8 6 327 APVLNSAKA 2 14 100 62 45 14 328 AGISRNSVA 0 9 61 62 21 21 329 ARSNNTIKA 1 7 73 61 24 32 330 AGVLRNSIA 2 6 73 61 45 28 331 ALLRNSTKA 0 5 58 61 20 69 332 AQIHPNSVA 1 5 79 61 43 24 333 AYIHNSTKA 3 13 85 60 46 55 334 ALLRILLKA 0 2 43 60 12 41 335 APRKNNNSA 1 18 83 59 21 12 336 AGIVANAIA 6 17 123 59 60 13 337 APRKNTVNA 1 7 66 59 25 9 338 ALLRISTKA 0 2 44 59 22 18 339 APGSRKAAA 0 2 32 59 9 1 340 APKAKGGGA 0 23 74 58 31 6 341 APARQKSGA 3 12 62 58 21 9 342 AKSKLGVVA 5 8 84 58 22 15 343 APRGTGKAA 1 8 27 58 12 3 344 APVADVTKA 1 5 83 58 47 60 345 AKITNASKA 0 5 43 58 12 52 346 APRKQTTSA 0 4 26 58 9 4 347 ALLRNANKA 0 3 49 58 36 10 348 ARKYPVSLA 0 1 20 58 8 34 349 APRGNEVKA 0 4 32 57 13 8 350 AWDECVTKA 0 2 48 57 37 12 351 ARKWQQFEA 0 1 13 57 9 8 352 ASLTNTVKA 0 0 39 57 14 29 353 AGLANAVRA 5 27 118 56 31 44 354 ARSGNKVNA 3 11 71 56 30 30 355 APRNNSSKA 1 2 28 56 6 17 356 AFSHPNMIA 2 10 64 55 23 28 357 APMTNKVSA 1 5 79 55 36 18 358 AGSFQVGSA 0 3 28 54 8 37 359 ALYEFYFKA 0 1 46 54 15 14 360 APRASGSKA 2 1 32 54 16 5 361 AGRFIWMRA 0 0 11 54 8 49 362 ALGSNSVRA 7 45 82 53 44 59 363 AGSFIVLDA 0 1 12 53 8 21 364 APGHKAAKA 0 0 20 53 7 6 365 APIKAVKTA 2 12 46 52 15 7 366 APMSNRAAA 0 8 58 52 21 33 367 APLMNKVVA 0 8 86 52 59 16 368 ARYMGNSIA 2 7 78 52 33 11 369 APRVAKPLA 1 7 42 52 17 5 370 ARLGNASKA 1 6 33 52 17 34 371 ARKVRVGVA 0 0 18 52 7 35 372 ASMNNSTKA 5 16 100 51 49 33 373 ALVRNDTRA 5 13 59 51 21 50 374 APAMNITKA 2 7 65 51 26 24 375 APLNKKLSA 1 4 38 51 11 3 376 APYRQCYEA 1 3 41 51 12 16 377 APKLATTKA 0 3 25 51 12 4 378 APAWVKVTA 0 2 12 51 9 1 379 APLTNAVKA 0 0 12 51 15 44 380 AGRLHIGVA 0 0 19 51 9 41 381 AGVIMGREA 0 0 13 51 5 22 382 APLPNSIKA 1 0 49 51 26 18 383 APSGKKTSA 0 0 11 51 10 0 384 APRVSGAKA 1 5 32 50 6 1 385 ARVDNKVKA 0 4 21 50 11 27 386 ARKVHIRVA 0 1 17 50 8 33 387 AGSIQGDMA 1 0 22 50 13 88 388 AGKFHSTDA 0 0 14 50 14 46 389 AGSISRICA 0 0 15 50 8 13 390 AGISSNKTA 4 14 69 49 24 14 391 APHVNTVRA 1 13 64 49 24 27 392 ALRNKAAQA 0 5 38 49 18 10 393 APRLNEVKA 2 4 64 49 22 17 394 AGVHMNSIA 0 4 54 49 36 16 395 APFTDSTKA 0 1 20 49 4 59 396 AARYHGSEA 0 1 10 49 3 14 397 APAGNEVKA 2 1 62 49 29 12 398 AKVHIIEVA 0 0 14 49 15 24 399 AGRCMAEVA 0 0 9 49 3 9 400 APLAKSSKA 0 0 22 49 5 1 401 APVSNTTRA 2 13 64 48 27 18 402 AGVVTNHVA 0 11 84 48 37 9 403 AWDEDVTKA 2 6 38 48 25 28 404 ALTANTVKA 1 3 38 48 21 45 405 ALLRDTVKA 0 3 25 48 13 44 406 AQRYHGSEA 0 2 11 48 4 58 407 ARVRRGAVA 0 2 37 48 17 6 408 APLVKTTKA 0 1 18 48 9 2 409 AAKYHGPPA 0 0 13 48 5 27 410 AGIRNNSTA 3 19 100 47 41 37 411 AKTGGKVAA 2 19 78 47 29 10 412 ARFPAGSLA 5 12 99 47 44 9 413 APGGKANKA 0 5 24 47 16 1 414 AYTKKSVAA 3 3 45 47 28 7 415 APGTNVIKA 0 1 54 47 31 13 416 AGSGMILRA 0 1 24 47 6 12 417 APKGTTAKA 0 1 31 47 16 1 418 ARKIHFGCA 0 0 6 47 4 68 419 ALTTNSIRA 6 16 88 46 41 38 420 ARWQIFTKA 0 8 49 46 21 34 421 AGSVNSVKA 3 6 54 46 34 28 422 APSATKNKA 0 1 21 46 3 1 423 ARKVHIECA 0 0 13 46 7 21 424 AAAGNQVKA 26 45 154 45 64 38 425 AMVSNATKA 3 14 122 45 56 46 426 AGIVTNHVA 1 10 80 45 42 16 427 ALSLNATKA 0 7 58 45 17 25 428 APLANTVKA 0 3 25 45 19 48 429 APYRNATKA 0 3 45 45 19 30 430 AGRCILKVA 0 0 16 45 7 18 431 AWSRSPNAA 2 18 90 44 45 39 432 AMASNSVRA 3 15 56 44 29 54 433 AMAQNSVKA 7 14 122 44 51 64 434 AGIQNNHIA 0 14 95 44 43 18 435 APLKLKAAA 1 4 43 44 19 7 436 APYHIATKA 0 3 39 44 20 6 437 ARWRMLLKA 0 0 41 44 22 17 438 APKKSGSPA 0 12 69 43 33 5 439 ARMSNKTSA 0 8 38 43 12 35 440 AGRLTNQIA 2 8 59 43 25 11 441 APRAGKAAA 1 7 59 43 16 6 442 AGTKNMIKA 3 5 49 43 29 21 443 ARKIHLDTA 0 0 10 43 5 47 444 ARMSNESRA 10 19 84 42 41 31 445 AVVSNAAQA 3 10 47 42 10 56 446 APRTVGNKA 0 7 28 42 13 4 447 APSVDLTKA 1 6 48 42 11 39 448 APRKNSAAA 0 6 51 42 16 16 449 APIGNTTRA 0 5 36 42 13 13 450 AKYIPGTLA 1 5 48 42 17 6 451 APRKPGVQA 0 5 44 42 9 3 452 APRKTSATA 0 3 29 42 10 3 453 APFADSTKA 0 2 21 42 14 37 454 APHTKSKSA 0 2 11 42 10 1 455 ARKFRSTDA 0 1 12 42 5 68 456 AGSIRSDLA 0 1 14 42 7 7 457 ASYEDTVKA 1 0 34 42 6 32 458 ALLRIRLRA 0 0 29 42 13 15 459 ARRCILRVA 0 0 11 42 5 11 460 AGTLNAIKA 7 13 78 41 39 24 461 AQRHNDTRA 9 12 101 41 37 40 462 ARKLQSAQA 5 10 44 41 14 20 463 AKVKGTSAA 3 10 53 41 23 10 464 APRSVQKSA 1 9 56 41 31 4 465 APRGNNLKA 0 3 28 41 8 5 466 APYHNVTKA 1 2 50 41 25 8 467 AGRCMARVA 0 1 7 41 6 38 468 ARKWYDTEA 0 0 17 41 9 13 469 ARKFHSIDA 0 0 12 41 5 8 470 AKKIDNRVA 1 7 69 40 28 28 471 AGAHPNSLA 0 3 43 40 28 10 472 APMGRKAAA 0 3 17 40 14 7 473 AGKWHDTEA 0 0 21 40 8 19 474 APFYEFTKA 0 0 31 40 12 14 475 APNRKSATA 1 13 72 39 24 4 476 APSGNSSRA 2 10 39 39 13 10 477 AAQGNTVRA 2 9 54 39 21 30 478 APRTKSIVA 0 9 59 39 34 6 479 APHLNLAKA 1 8 55 39 16 17 480 APRGAKSSA 0 5 25 39 12 1 481 APKITKPSA 0 3 34 39 13 6 482 ARKYRSDLA 0 2 16 39 14 14 483 ARKYQSSLA 0 0 18 39 10 29 484 ARKWRQSEA 0 0 15 39 5 25 485 AVKMHMPDA 0 0 18 39 4 22 486 AKVGGKAAA 0 10 39 38 10 2 487 APRQVSKTA 1 7 36 38 11 9 488 APATTKVKA 0 5 18 38 7 1 489 ARKIHDGPA 0 3 21 38 5 13 490 AGILRNTIA 3 3 46 38 18 8 491 APSSGKKVA 0 3 33 38 13 1 492 APRSAKPAA 0 3 29 38 18 0 493 ARWRIFTKA 1 2 42 38 24 20 494 AKVNNLTKA 2 2 20 38 17 19 495 APNSNIIKA 0 2 35 38 8 13 496 ARKWHDAEA 0 1 18 38 8 24 497 AGSFHTETA 0 1 11 38 3 11 498 ARKYPVGFA 0 0 19 38 3 25 499 ALRGVKVTA 0 0 23 38 6 1 500 APLGKKISA 0 0 9 38 8 0 501 ARATNEVRA 2 17 74 37 35 38 502 APGGNEVRA 1 13 71 37 30 12 503 ALLGNAVKA 2 8 64 37 25 38 504 APHSNRVSA 1 8 49 37 18 16 505 APRSKNAVA 0 6 62 37 20 5 506 APSINKVKA 0 5 4 37 3 3 507 APAANTVRA 2 4 51 37 22 20 508 ALCRNSAKA 0 3 34 37 9 28 509 APLRSAVKA 1 3 32 37 9 3 510 APLKKHAAA 0 3 18 37 5 2 511 APLTNTVGA 0 1 34 37 12 33 512 ALLIILVKA 0 1 26 37 9 8 513 ALMSNRATA 0 1 38 37 20 7 514 APLVNAVKA 0 0 26 37 12 23 515 APSSKKATA 0 0 12 37 2 0 516 AKFIIGSLA 4 12 83 36 35 6 517 APSTNRVTA 1 7 54 36 17 8 518 APKAPNKSA 0 4 45 36 9 5 519 AKVKLGAAA 3 3 26 36 9 12 520 AEVSVPDLA 0 1 12 36 7 15 521 AGSFIGTDA 0 0 10 36 0 35 522 AEVSYSTDA 0 0 8 36 4 19 523 AGRCIAEVA 0 0 14 36 7 7 524 ARKYQSDFA 0 0 21 36 6 7 525 AALGNVVRA 9 19 75 35 37 40 526 AVASNVVKA 2 14 70 35 29 31 527 ALAGNAVKA 5 14 59 35 29 23 528 APASNVARA 2 12 49 35 22 14 529 AYGHPIVIA 3 3 61 35 21 11 530 ALWLNLVKA 0 2 38 35 9 25 531 ALSVNLTKA 2 2 78 35 54 19 532 APLRNSTKA 0 2 11 35 5 18 533 ALYHPNKVA 0 2 33 35 19 17 534 ARRYQSDLA 0 1 10 35 3 21 535 AAKAMKLGA 0 13 46 34 20 12 536 AAMGNASRA 2 8 51 34 34 44 537 APRALKITA 0 5 47 34 18 5 538 ALSLNLVKA 3 5 52 34 31 2 539 ALVANVTKA 0 4 50 34 30 11 540 AKFVPGTLA 2 3 65 34 33 14 541 ASIHPNAIA 1 3 42 34 23 9 542 AKMKVGVSA 0 3 26 34 10 4 543 APVGAKKGA 0 2 19 34 6 0 544 ASYEYTVKA 0 1 17 34 12 14 545 AQEVSVDLA 0 1 17 34 13 12 546 AGVIMESEA 0 0 8 34 4 29 547 AEGACIEVA 0 0 7 34 8 16 548 AVLFRNIPA 2 10 41 33 15 107 549 APKRSNATA 0 6 34 33 18 4 550 ALRQNLVKA 1 5 41 33 16 26 551 ALRINNVKA 3 4 30 33 7 16 552 APRKAGTVA 1 4 26 33 15 7 553 AQRLNNTKA 0 3 13 33 9 28 554 APLADLTKA 0 2 25 33 4 32 555 APLADTVKA 0 1 15 33 13 38 556 AGRCAIEVA 0 1 10 33 3 17 557 ARKYQPDLA 0 1 22 33 7 12 558 ARKIRLDAA 0 0 6 33 2 43 559 ARRCILSAA 0 0 10 33 7 8 560 AEVSSPDLA 0 0 10 33 4 7 561 AGVIMGSEA 0 0 7 33 0 7 562 AVKYQSDLA 0 0 13 33 8 5 563 APRQAKVAA 1 0 17 33 12 0 564 AQMTNQVKA 7 13 106 32 45 36 565 AGQSNQTRA 2 13 71 32 34 12 566 APVRAATKA 1 13 38 32 10 2 567 AKTKSANSA 0 8 33 32 15 25 568 AFSAHPNKA 0 7 59 32 19 14 569 ARIKGGVPA 0 7 51 32 10 10 570 APWFRDNAA 0 6 35 32 20 2 571 APSKGKSNA 0 5 35 32 9 1 572 APRTNNTVA 0 4 39 32 11 12 573 APKTSKSSA 0 4 48 32 18 5 574 ARKYQAASA 1 3 17 32 3 19 575 APKANLAKA 1 3 32 32 10 6 576 AGVIMGPEA 0 1 12 32 5 34 577 ASYGIRLKA 0 1 16 32 5 28 578 APRTGATKA 0 1 20 32 6 2 579 AARGVKVTA 0 1 6 32 5 2 580 AGSIRSDMA 0 0 12 32 11 39 581 ARIVILVKA 0 0 36 32 11 16 582 ALLRIPTKA 0 0 25 32 8 7 583 AAWGVKVTA 0 0 13 32 6 3 584 APTKKTAVA 0 13 48 31 13 1 585 AIMLNQVKA 5 11 86 31 37 20 586 APGLNYVKA 2 11 53 31 21 13 587 ARKLHSGPA 0 7 20 31 11 23 588 AKWKSGASA 1 5 28 31 12 11 589 AWKAQKTSA 1 5 11 31 9 8 590 APRTKGTAA 0 4 56 31 23 3 591 APRHSKVTA 0 3 43 31 14 2 592 AGTANVTKA 1 2 38 31 24 30 593 ALLGNMTKA 0 2 27 31 14 6 594 ARKVHIEIA 0 1 2 31 1 18 595 AEVSCGPPA 0 1 7 31 8 10 596 AKAKAGVTA 0 1 21 31 11 8 597 ALILNATKA 0 0 26 31 5 15 598 ARSVNLTKA 0 0 41 31 16 9 599 ASYEYGAKA 0 0 27 31 4 9 600 ALKYRGPPA 0 0 10 31 1 9

Example 2: Rationale Design of AAV5 Capsid Proteins with Increase Transduction Efficiency

In conjunction with the library-based approach described in Example 1, a rational-design approach was used to identify AAV5 capsid proteins that confer increased transduction efficiency. Surface exposed residues were selected. Substitution of these amino acids were tested in the hCF assay as described in Example 1. The substitutions S651A, T578A, or T582A in the AAV5 capsid resulted in improved human cardiac fibroblast transduction at an multiplicity of infection of 100,000 vg/cell, 72 hours following infection (FIG. 9).

In follow-up experiments, the substitutions identified in this rational-design experiment are tested in combination with one another and in combination with the insertions disclosed in Tables 1 and 2.

Example 3: Comparative Testing of AAVx1 Versus Wild-Type AAV5

An AAV5 capsid having two or three of S651A, T578A, and/or T582A substitutions (AAVx1) was generated. The capsid sequence was as follows:

(SEQ ID NO: 73) MSFVDHPPDWLEEVGEGLREFLGLEAGPPKPKPNQQHQDQARGLVLPGYNY LGPGNGLDRGEPVNRADEVAREHDISYNEQLEAGDNPYLKYNHADAEFQEK LADDTSFGGNLGKAVFQAKKRVLEPFGLVEEGAKTAPTGKRIDDHFPKRKK ARTEEDSKPSTSSDAEAGPSGSQQLQIPAQPASSLGADTMSAGGGGPLGDN NQGADGVGNASGDWHCDSTWMGDRVVTKSTRTWVLPSYNNHQYREIKSGSV DGSNANAYFGYSTPWGYFDFNRFHSHWSPRDWQRLINNYWGFRPRSLRVKI FNIQVKEVTVQDSTTTIANNLTSTVQVFTDDDYQLPYVVGNGTEGCLPAFP PQVFTLPQYGYATLNRDNTENPTERSSFFCLEYFPSKMLRTGNNFEFTYNF EEVPFHSSFAPSQNLFKLANPLVDQYLYRFVSTNNTGGVQFNKNLAGRYAN TYKNWFPGPMGRTQGWNLGSGVNRASVSAFATTNRMELEGASYQVPPQPNG MTNNLQGSNTYALENTMIFNSQPANPGTTATYLEGNMLITSESETQPVNRV AYNVGGQMATNNQSST X APA X GTYNLQEIVPGSVWMERDVYLQGPIWAKIP ETGAHFHPSPAMGGFGLKHPPPMMLIKNTPVPGNITSF X DVPVSSFITQYS TGQVTVEMEWELKKENSKRWNPEIQYTNNYNDPQFVDFAPDSTGEYRTTRP IGTRYLTRPL, where X = A, G, V, S, or T

To test ability to transduce human cardiac fibroblasts (hCFs), hCFs were infected with AAV5.CAG-GFP or AAVx1 (T582A+S651A) at a MOI ranging from 1,000 to 1,000,000. 48 hours after infection, cells were harvested and GFP expression was quantified using flow cytometry. At all tested MOIs, percent transduction (FIG. 10A), GFP expression (FIG. 10B), and relative transduction (FIG. 10C) were increased compared to the wild-type AAV5 capsid.

The ability of AAVx1 vectors to deliver a functional cargo was tested by generating AAV5 and AAVx1 vectors comprising an expression cassette encoding myocardin and ASCL1 (MyA). The internal deletion of mycocardin MyΔ3 described in Int'l Pat. Appl. No. PCT/US2019/049150 and U.S. Prov. Pat. Appl. No. 62/788,479—each of which is incorporated by reference herein—was used. Strikingly, AAVx1 vector performed on average 9-fold better than AAV5 vector, based on transgene and marker expression at day 7 post-infection (shown in Table 3).

TABLE 3 MYOCD ASCL1 ACTC1 CASQ2 NPPA PLN TNNT2 NO INF. 0.9 0.7 1.1 1.3 1.3 1.0 1.1 1.1 1.5 0.9 0.9 1.4 1.1 1.0 AAV5: 111.3 772.4 12.5 27.9 779.2 20.0 129.0 MYΔ3A + 117.0 772.2 11.8 29.5 512.2 18.0 120.0 MOI 400K AAV5: 219.0 1345.2 17.4 40.6 756.9 35.5 200.9 MYΔ3A + 176.2 1230.6 17.1 44.9 922.6 30.5 171.6 MOI 1.2M AAVx1: 897.5 5743.7 119.6 321.9 6165.3 143.5 1010.5 MYΔ3A + 811.0 5619.1 103.8 288.4 5875.2 127.9 972.3 MOI 400K AAVx1: 1680.1 11924.0 188.8 587.3 10753.4 234.1 2013.0 MYΔ3A + 1683.6 11225.0 196.2 490.3 10787.2 246.7 1795.3 MOI 1.2M

Example 4: In Vivo Transduction of Cardiac Tissue with AAVx1

Testing in Mice

To evaluate in vivo transduction, AAV5 or AAVx1 (T582A+S651A) capsid was used to deliver an expression cassette encoding a GFP reporter in mice using the LAD-ligation mouse model of myocardial infarction (MI), with injection of the AAV vector performed epicardially at the time of injury. A single vector dose of 1.2×10¹¹ genome copies (GC) was delivered to the heart of each subject by intracardiac injection. Seven days following injection, animals were sacrificed and their hearts dissociated by enzymatic digestion. Dissociated cells were stained with an endothelial marker (CD31) and fibroblast marker (Thy-1) and sorted using fluorescence activated cell sorting (FACs). GFP+, Thy-1+ and CD31− cells were classified as transduced cardiac fibroblasts, while, GFP−, Thy-1+ and CD31− cells were classified as non-transduced cardiac fibroblasts. The number of transduced cells were normalized to AAV5. As shown in FIG. 11, in vivo transduction of cardiac fibroblast cells (CF) was more than 4-fold greater using AAVx1 vector than AAV5 vector.

For functional in vivo testing, AAVx1 (T582A+S651A) capsid was used to deliver an expression cassette encoding myocardin and ASCL1 (MyA). The AAVx1 vector was tested in mice using the LAD-ligation mouse model of myocardial infarction (MI), with injection of the AAV vector performed epicardially at the time of injury. A single vector dose of 1.2×10¹¹ genome copies (GC) was delivered to the heart of each subject by intracardiac injection.

Efficacy was assessed by echocardiography at 2, 4, 6, and 8 weeks post-injection. The AAVx1 vector significantly preserved cardiac function (ejection fraction) compared to the GFP-encoding control (FIG. 12).

Testing in Pigs

The AAVx1 vector was further tested in a pig myocardial infarction (MI) model. MyA was packaged into AAVx1 capsid and injected epicardially into the border zone of pig hearts 28 days after a 90-minute balloon occlusion to introduce ischemic injury. In parallel, infarcted pigs were also injected with formulation buffer, so that each group consisted of ten animals. Echocardiography was performed 3-weeks, 5-weeks, 7-weeks and 9-weeks post-injection. Pigs that received AAVx1 vector demonstrated significant improvement in ejection fraction relative to control 5-weeks, 7-weeks and 9-weeks post-injection (FIG. 13). Thus, treatment with the an AAVx1 vector resulted in an average 10% improvement in cardiac performance above pre-dose baseline. 

What is claimed is:
 1. A recombinant adeno-associated virus (rAAV) virion, comprising: a) an AAV5 capsid protein, wherein the capsid protein comprises one or more substitutions selected from S651A, S651G, S651V, S651L, S651I, T578A, T578G, T578V, T578L, T578I, T582A, T582G, T582V, T582L, or T582I compared to a parental AAV5 capsid; and b) a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product.
 2. The rAAV virion of claim 2, wherein the AAV5 capsid protein comprises two or more substitutions selected from S651A or S651V; T578A or T578V; and/or T582A or T582V.
 3. The rAAV virion of claim 2, wherein the AAV5 capsid protein comprises T582A and S651A substitutions.
 4. The rAAV virion of claim 3, wherein the AAV5 capsid protein comprises T578A and T582A substitutions.
 5. The rAAV virion of claim 3, wherein the AAV5 capsid protein comprises T578A and S651A substitutions.
 6. The rAAV virion of claim 3, wherein the AAV5 capsid protein comprises S651A, T578A, and T582A substitutions.
 7. The rAAV virion of any one of claims 1 to 6, wherein the AAV5 capid protein shares at least 95% identity, at least 98% identity, or at least 99% identity to SEQ ID NO:
 73. 8. An AAV5 capsid protein comprising one or more substitutions selected from S651A, S651G, S651V, S651L, S651I, T578A, T578G, T578V, T578L, T578I, T582A, T582G, T582V, T582L, or T582I compared to a parental AAV5 capsid.
 9. The AAV5 capsid protein of claim 8, wherein the capsid protein comprises two or more substitutions selected from S651A or S651V; T578A or T578V; or T582A or T582V.
 10. The AAV5 capsid protein of claim 9, wherein the capsid protein comprises T582A and S651A substitutions.
 11. The AAV5 capsid protein of claim 9, wherein the capsid protein comprises T578A and T582A substitutions.
 12. The AAV5 capsid protein of claim 9, wherein the capsid protein comprises T578A and S651A substitutions.
 13. The AAV5 capsid protein of claim 9, wherein the capsid protein comprises S651A, T578A, and T582A substitutions.
 14. The AAV5 capsid protein of any one of claims 8 to 13, wherein the capid protein shares at least 90% identity to SEQ ID NO:
 73. 15. The AAV5 capsid protein of any one of claims 8 to 13, wherein the capid protein shares at least 95% identity, at least 98% identity, or at least 99% identity to SEQ ID NO:
 73. 16. A polynucleotide encoding the AAV5 capsid protein of any one of claims 8 to
 15. 17. A pharmaceutical composition comprising the rAAV virion of any one of claims 1 to
 7. 18. A method of transducing a cardiac cell, comprising contacting the cardiac cell with an rAAV virion according to any one of claims 1 to 7, wherein the rAAV virion transduces the cardiac cell.
 19. A method of delivering one or more gene products to a cardiac cell, comprising contacting the cardiac cell with an rAAV virion according to any one of claims 1 to 7, wherein the cardiac cell expresses the gene product.
 20. The method of claim 18 or claim 19, wherein the one or more gene products comprise a polypeptide, optionally selected from cardiac troponin T; a cardiac sarcomeric protein; β-myosin heavy chain; myosin ventricular essential light chain 1; myosin ventricular regulatory light chain 2; cardiac α-actin; α-tropomyosin; cardiac troponin I; cardiac myosin binding protein C; four-and-a-half LIM protein 1; titin; Y-AMP-activated protein kinase subunit gamma-2; troponin I type 3, myosin light chain 2, actin alpha cardiac muscle 1; cardiac LIM protein; caveolin 3 (CAV3); galactosidase alpha (GLA); lysosomal-associated membrane protein 2 (LAMP2); mitochondrial transfer RNA glycine (MTTG); mitochondrial transfer RNA isoleucine (MTTI); mitochondrial transfer RNA lysine (MTTK); mitochondrial transfer RNA glutamine (MTTQ); myosin light chain 3 (MYL3); troponin C (TNNC1); transthyretin (TTR); sarcoendoplasmic reticulum calcium-ATPase 2a (SERCA2a); stromal-derived factor-1 (SDF-1); adenylate cyclase-6 (AC6); β-ARKct (β-adrenergic receptor kinase C terminus); fibroblast growth factor (FGF); platelet-derived growth factor (PDGF); vascular endothelial growth factor (VEGF); hepatocyte growth factor; hypoxia inducible growth factor; thymosin beta 4 (TMSB4X); nitric oxide synthase-3 (NOS3); apoplipoprotein-E (ApoE); and superoxide dismutase (SOD); S100A1
 21. The method of claim 18 or claim 19, wherein the one or more gene products comprise one or more reprogramming factors, optionally selected from ASCL1, MYOCD, MEF2C, TBX5, CCNB1, CCND1, CDK1, CDK4, AURKB, OCT4, BAF60C, ESRRG, GATA4, GATA6, HAND2, IRX4, ISLL, MESP1, MESP2, NKX2.5, SRF, TBX20, and ZFPM2.
 22. The method of claim 21, wherein the method reprograms the cardiac cell into a cardiac cardiomyocyte.
 23. A method of treating a cardiac pathology in a subject in need thereof, comprising administering a therapeutically effective amount of a pharmaceutical composition according to claim 17 to the subject, wherein the rAAV virion transduces cardiac tissue.
 24. The method of claim 23, wherein the rAAV virion is administered by epicardial injection.
 25. The method of claim 23, wherein the rAAV virion is administered by intravenous injection, intramuscular injection, intraperitoneal injection, intracardiac injection, intracardiac catheterization, direct intramyocardial injection, transvascular administration, antegrade intracoronary injection, retrograde injection, transendomyocardial injection, or molecular cardiac surgery with recirculating delivery (MCARD).
 26. A recombinant adeno-associated virus (rAAV) virion, comprising: a) an AAV5 capsid protein, wherein the capsid protein comprises an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence; and b) a heterologous nucleic acid comprising a nucleotide sequence encoding a gene product,
 27. The rAAV virion of claim 26, wherein the insertion site is between any two, optionally adjacent, amino acids at positions in the parental sequence corresponding to 560 to 594 of SEQ ID NO:
 1. 28. The rAAV virion of claim 27, wherein the insertion site is between adjacent amino acids in the parental sequence corresponding to 574 and 575 of SEQ ID NO:
 1. 29. The rAAV virion of any one or claims 26 to 28, wherein the insertion is a peptide of formula: -X₀-X₁-X₂-X₃-X₄-X₅-X₆-X₇-X₈- wherein X₀ and X₈ are each independently A, S, G, or absent (SEQ ID NO: 1102).
 30. The rAAV virion of claim 29, wherein the insertion is a peptide of formula: -A-X₁-X₂-X₃-X₄-X₅-X₆-X₇-A- wherein: a) X₁ is P, R, or G; b) X₂ is K, L, or R; c) X₃ is any amino acid; d) X₄ is N, H, K, or Q; e) X₅ is any amino acid, or optionally X₅ is G, K, or S; f) X₆ is any amino acid, or optionally X₆ is T or V; and g) X₇ is any amino acid, or optionally X₇ is K or V (SEQ ID NO: 1103).
 31. The rAAV virion of claim 30, wherein the insertion comprises an amino acid sequence selected from SEQ ID NOs: 101-600.
 32. The rAAV virion of claim 30, wherein the insertion comprises an amino acid sequence selected from RKVHIEV (SEQ ID NO: 81), RKYQSDL (SEQ ID NO: 82), PLTNTVK (SEQ ID NO: 83), LKYHGPP (SEQ ID NO: 84), RKYQGDM (SEQ ID NO: 85), RKFHSTD (SEQ ID NO: 86), RKHHGLE (SEQ ID NO: 87), PGTNVTK (SEQ ID NO: 88), RKMHMPD (SEQ ID NO: 89), PLKKIVQ (SEQ ID NO: 90), PLGKKTS (SEQ ID NO: 91), PRGVKVT (SEQ ID NO: 92), PLAKSKS (SEQ ID NO: 93), PRTKGAV (SEQ ID NO: 94), and PSGRKAT (SEQ ID NO: 95).
 33. The rAAV virion of claim 30, wherein the insertion comprises an amino acid sequence selected from ARKVHIEVA (SEQ ID NO: 101), ARKYQSDLA (SEQ ID NO: 102), APLTNTVKA (SEQ ID NO: 103), ALKYHGPPA (SEQ ID NO: 104), ARKYQGDMA (SEQ ID NO: 105), ARKFHSTDA (SEQ ID NO: 106), ARKHHGLEA (SEQ ID NO: 107), APGTNVTKA (SEQ ID NO: 108), ARKMHMPDA (SEQ ID NO: 109), APLKKIVQA (SEQ ID NO: 110), APLGKKTSA (SEQ ID NO: 111), APRGVKVTA (SEQ ID NO: 112), APLAKSKSA (SEQ ID NO: 113), APRTKGAVA (SEQ ID NO: 114), APSGRKATA (SEQ ID NO: 115).
 34. The rAAV virion of claim 30, wherein the insertion comprises the amino acid sequence PLTNTVK (SEQ ID NO: 83) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLTNTVK (SEQ ID NO: 83).
 35. The rAAV virion of claim 30, wherein the insertion comprises the amino acid sequence PLKKIVQ (SEQ ID NO: 90) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLKKIVQ (SEQ ID NO: 90).
 36. The rAAV virion of any one of claims 26 to 35, wherein the capsid protein comprises one or more substitutions selected from S651A, T578A, or T582A compared to a parental AAV5 capsid.
 37. The rAAV virion of claim 36, wherein the AAV5 capsid protein comprises two or more substitutions selected from S651A, T578A, or T582A.
 38. The rAAV virion of claim 36, wherein the AAV5 capsid protein comprises T582A and S651A substitutions.
 39. The rAAV virion of claim 36, wherein the AAV5 capsid protein comprises T578A and T582A substitutions.
 40. The rAAV virion of claim 36, wherein the AAV5 capsid protein comprises T578A and S651A substitutions.
 41. The rAAV virion of claim 36, wherein the AAV5 capsid protein comprises S651A, T578A, and T582A substitutions.
 42. The rAAV virion of any one of claims 26 to 41, wherein the rAAV virion exhibits increased transduction efficiency in cardiac cells compared to an AAV virion comprising the parental sequence.
 43. The rAAV virion of claims 26 to 42, wherein the rAAV virion exhibits increased transduction efficiency in human cardiac fibroblast (hCF) cells compared to an AAV virion comprising the parental sequence.
 44. An AAV5 capsid protein, wherein the capsid protein comprises an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence.
 45. The AAV5 capsid protein of claim 44, wherein the insertion site is between adjacent amino acids in the parental sequence corresponding to 574 and 575 of SEQ ID NO:
 1. 46. The AAV5 capsid protein of claim 44 or claim 45, wherein the insertion is a peptide of formula: -X₀-(X)_(n)-X₁₀- wherein n is 5-9, and wherein X₀ and X₁₀ are each independently A, S, G, or absent (SEQ ID NO: 1101).
 47. The AAV5 capsid protein of claim 44 or claim 45, wherein the insertion is a peptide of formula: -X₀-X₁-X₂-X₃-X₄-X₅-X₆-X₇-X₈- wherein X₀ and X₈ are each independently A, S, G, or absent (SEQ ID NO: 1102).
 48. The AAV5 capsid protein of claim 47, wherein the insertion is a peptide of formula: -A-X₁-X₂-X₃-X₄-X₅-X₆-X₇-A- wherein: a) X₁ is P, R, or G; b) X₂ is K, L, or R c) X₃ is any amino acid; d) X₄ is N, H, K, or Q; e) X₅ is any amino acid, or optionally X₅ is G, K, or S; f) X₆ is any amino acid, or optionally X₆ is T or V; and g) X₇ is any amino acid, or optionally X₇ is K or V (SEQ ID NO: 1103).
 49. The AAV5 capsid protein of claim 48, wherein the insertion comprises an amino acid sequence selected from SEQ ID NOs: 101-600.
 50. The AAV5 capsid protein of claim 48, wherein the insertion comprises an amino acid sequence selected from RKVHIEV (SEQ ID NO: 81), RKYQSDL (SEQ ID NO: 82), PLTNTVK (SEQ ID NO: 83), LKYHGPP (SEQ ID NO: 84), RKYQGDM (SEQ ID NO: 85), RKFHSTD (SEQ ID NO: 86), RKHHGLE (SEQ ID NO: 87), PGTNVTK (SEQ ID NO: 88), RKMHMPD (SEQ ID NO: 89), PLKKIVQ (SEQ ID NO: 90), PLGKKTS (SEQ ID NO: 91), PRGVKVT (SEQ ID NO: 92), PLAKSKS (SEQ ID NO: 93), PRTKGAV (SEQ ID NO: 94), and PSGRKAT (SEQ ID NO: 95).
 51. The AAV5 capsid protein of claim 48, wherein the insertion comprises an amino acid sequence selected from ARKVHIEVA (SEQ ID NO: 101), ARKYQSDLA (SEQ ID NO: 102), APLTNTVKA (SEQ ID NO: 103), ALKYHGPPA (SEQ ID NO: 104), ARKYQGDMA (SEQ ID NO: 105), ARKFHSTDA (SEQ ID NO: 106), ARKHHGLEA (SEQ ID NO: 107), APGTNVTKA (SEQ ID NO: 108), ARKMHMPDA (SEQ ID NO: 109), APLKKIVQA (SEQ ID NO: 110), APLGKKTSA (SEQ ID NO: 111), APRGVKVTA (SEQ ID NO: 112), APLAKSKSA (SEQ ID NO: 113), APRTKGAVA (SEQ ID NO: 114), APSGRKATA (SEQ ID NO: 115).
 52. The AAV5 capsid protein of claim 48, wherein the insertion comprises the amino acid sequence PLTNTVK (SEQ ID NO: 83) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLTNTVK (SEQ ID NO: 83).
 53. The AAV5 capsid protein of claim 48, wherein the insertion comprises the amino acid sequence PLKKIVQ (SEQ ID NO: 90) or a sequence comprising at most 1, 2, 3, or 4 amino-acid substitutions relative to PLKKIVQ (SEQ ID NO: 90).
 54. The AAV5 capsid protein of any one of claims 44 to 53, wherein the capsid protein comprises one or more substitutions selected from S651A, T578A, or T582A compared to a parental AAV5 capsid.
 55. The AAV5 capsid protein of claim 54, wherein the AAV5 capsid protein comprises two or more substitutions selected from S651A, T578A, or T582A.
 56. A polynucleotide encoding the AAV5 capsid protein of any one of claims 44 to
 55. 57. A pharmaceutical composition comprising the rAAV virion of any one of claims 26 to
 43. 58. A method of transducing a cardiac cell, comprising contacting the cardiac cell with an rAAV virion according to any one of claims 26 to 43, wherein the rAAV virion transduces the cardiac cell.
 59. A method of delivering one or more gene products to a cardiac cell, comprising contacting the cardiac cell with an rAAV virion according to any one of claims 26 to 43, wherein the cardiac cell expresses the gene product.
 60. The method of claim 58 or claim 59, wherein the one or more gene products comprise a polypeptide, optionally selected from cardiac troponin T; a cardiac sarcomeric protein; β-myosin heavy chain; myosin ventricular essential light chain 1; myosin ventricular regulatory light chain 2; cardiac α-actin; a-tropomyosin; cardiac troponin I; cardiac myosin binding protein C; four-and-a-half LIM protein 1; titin; Y-AMP-activated protein kinase subunit gamma-2; troponin I type 3, myosin light chain 2, actin alpha cardiac muscle 1; cardiac LIM protein; caveolin 3 (CAV3); galactosidase alpha (GLA); lysosomal-associated membrane protein 2 (LAMP2); mitochondrial transfer RNA glycine (MTTG); mitochondrial transfer RNA isoleucine (MTTI); mitochondrial transfer RNA lysine (MTTK); mitochondrial transfer RNA glutamine (MTTQ); myosin light chain 3 (MYL3); troponin C (TNNC1); transthyretin (TTR); sarcoendoplasmic reticulum calcium-ATPase 2a (SERCA2a); stromal-derived factor-1 (SDF-1); adenylate cyclase-6 (AC6); β-ARKct (β-adrenergic receptor kinase C terminus); fibroblast growth factor (FGF); platelet-derived growth factor (PDGF); vascular endothelial growth factor (VEGF); hepatocyte growth factor; hypoxia inducible growth factor; thymosin beta 4 (TMSB4X); nitric oxide synthase-3 (NOS3); apoplipoprotein-E (ApoE); and superoxide dismutase (SOD); S100A1
 61. The method of claim 58 or claim 59, wherein the one or more gene products comprise one or more reprogramming factors, optionally selected from ASCL1, MYOCD, MEF2C, TBX5, CCNB1, CCND1, CDK1, CDK4, AURKB, OCT4, BAF60C, ESRRG, GATA4, GATA6, HAND2, IRX4, ISLL, MESP1, MESP2, NKX2.5, SRF, TBX20, and ZFPM2.
 62. The method of claim 61, wherein the method reprograms the cardiac cell into a cardiac cardiomyocyte.
 63. A method of treating a cardiac pathology in a subject in need thereof, comprising administering a therapeutically effective amount of a pharmaceutical composition according to claim 57 to the subject, wherein the rAAV virion transduces cardiac tissue.
 64. The method of claim 63, wherein the rAAV virion is administered by epicardial injection.
 65. The method of claim 63, wherein the rAAV virion is administered by intravenous injection, intramuscular injection, intraperitoneal injection, intracardiac injection, intracardiac catheterization, direct intramyocardial injection, transvascular administration, antegrade intracoronary injection, retrograde injection, transendomyocardial injection, or molecular cardiac surgery with recirculating delivery (MCARD).
 66. A method of identifying AAV capsid proteins that confer on rAAV virions increased transduction efficiency in target cells, comprising: a) providing a population of rAAV virions whose rAAV genomes comprise a library of cap polynucleotides encoding variant AAV capsid proteins; b) contacting the population with target cells for a time sufficient to permit transduction of the cap polynucleotide into the target cells by the rAAV virions; and c) sequencing the cap polynucleotides from the target cells, thereby identifying AAV capsid proteins that confer increased transduction efficiency in the target cells.
 67. The method of claim 66, further comprising, before step (b), depleting the population of rAAV virions by contacting the population with non-target cells for time sufficient to permit attachment of the rAAV virions to the non-target cells.
 68. The method of claim 66 or claim 67, wherein the variant AAV capsid proteins are AAV5 capsid proteins.
 69. The method of any one of claims 66 to 68, wherein the variant capsid proteins each individually comprise an insertion with respect to a parental sequence of 5 to 11 amino acids at an insertion site in the GH loop of the parental sequence.
 70. The method of claim 69, wherein the insertion site is between any two, optionally adjacent, amino acids at positions in the parental sequence corresponding to 560 to 594 of SEQ ID NO:
 1. 71. The method of claim 69, wherein the insertion site is between adjacent amino acids in the parental sequence corresponding to 574 and 575 of SEQ ID NO:
 1. 72. The method of any one of claims 69 to 71, wherein the insertion is a peptide of formula: -X₀-X₁-X₂-X₃-X₄-X₅-X₆-X₇-X₈- wherein X₀ and X₈ are each independently A, S, G, or absent (SEQ ID NO: 1102). 